Welcome to the Panasonic Industry page on element14. Here you can find things such as our latest news, training videos, and product details. Additionally, you can engage with us in our forums.
Different kinds of electronic devices employ AC/DC converters as instrument to transform commercial AC power into DC power. They are necessary since the majority of electrical loads operate on DC rather than AC voltages. The size of an AC/DC converter varies depending on how much power the device needs. From the perspectives of saving space and portability, the smaller the size as compared to the same power, the better.
Downsizing has historically been a gradual process ever since AC/DC converters switched from linear to switching approaches.
But as is sometimes the case with AC adapters for notebook PCs, there have been notable reductions in size in recent years.
Such dramatic advances are frequently brought about by the introduction of low-loss GaN (gallium nitride) as a switching element in place of traditional Si, in addition to ongoing improvements in circuit topology.
Since approximately the year 2000, GaN has been used in power supplies. But the use of practical GaN has been gaining tremendous momentum in recent years.
Due to societal developments including the rise of mobile work and power shortages, there has been a growing demand for smaller size and improved efficiency. Additionally, GaN's own quality and productivity improvements have been matched.
GaN switching elements have lower switching losses than Si switching elements because they switch more quickly. As a result, if the switching frequency is kept constant compared to conventional Si, efficiency will be increased, heat will be lowered, and heat dissipation components will be made simpler.
Additionally, if employing smaller passive components, it is acceptable to use a higher switching frequency. GaN can maintain the same high efficiency that Si offered at a low switching frequency, even at greater switching frequencies.
Modern power supply designs are generally regarded as acceptable if they maintain the high power efficiency that earlier technologies attained. GaN's low loss advantage therefore frequently causes designs to be scaled down.
In order to reduce the size of the output capacitors for AC/DC converters that use GaN switches, Panasonic Industry offers a large selection of suitable polymer capacitors.
Let's first examine the operation of an output capacitor.
The output capacitor adds to the clean DC current output to the next circuit by absorbing the ripple current of the AC/DC converter. The capacitor will always produce ripple voltage when it takes in ripple current. This ripple voltage must be less than the limit values established for the application's safe functioning during design verification, which are typically less than 5% of the output voltage.
The impedance of the capacitor is the primary component for obtaining minimal ripple on a DC output voltage. The fundamental relationship is ripple voltage = ripple current x impedance (V=I*Z). Therefore, it is best to utilize capacitors with the lowest possible impedance at the switching frequency (where ripple current occurs).
GaN's reduced switching loss makes it possible to employ switching frequencies up to 500 kHz, compared to traditional Si's 100 kHz.
Polymer capacitors have a far lower impedance in this high-frequency region than with the more common liquid electrolytic capacitors. As a result, polymer capacitors can significantly lower ripple voltages, making them the optimum output capacitors for AC/DC converter systems that use GaN.
A low ESR conductive polymer substance is used as the electrolyte to provide polymer capacitors their low impedance.
Because of the low ESR, it can withstand more ripple currents than electrolytic capacitors.
Additionally, unlike liquid electrolytic capacitors, conductive polymer has a solid electrolyte, therefore its properties do not degrade over time or in low-temperature environments. These benefits of polymer capacitors influence client designs in various ways.
In some circumstances, raising the switching frequency can lower capacitance, which can result in significant cost and size reductions. Let's discuss one example of this.
The high-frequency AC/DC converter used in the evaluation example below operates between 200 and 400 kHz. Compared to electrolytic capacitors, polymer capacitors are able to implement the design with a significantly smaller area and fewer components.
This is a result of the aforementioned polymer capacitor's good temperature and frequency properties.
Electrolytic capacitor 63V 390uF vs Polymer capacitor 63V 33uF
At 48V output of the AC/DC converter
Measure the output ripple voltage at a maximum load of 3.2A including at lowest operating temperature for the worst condition.
Compare the measurement result between the originally equipped electrolytic capacitor 63V 390uF x 3 and proposed Panasonic polymer capacitor 63V 33uF x 1-3.
Even though the polymer capacitor has a smaller capacitance, its excellent frequency characteristics suppress ripple voltages to the same level.
When looking at the lowest operating temperature -30°C, it shows a possibility to design only with a single polymer capacitor.
And this will be stable even at the end of life (after 50,000 hours).
The need for these high-frequency AC/DC converters, which is growing with GaN adaptations, is being met by Panasonic.
Panasonic is a leader in polymer capacitors and offers a range of solutions up to 100V that make use of our special high-performance and high-reliability technology. They are extensively utilized for 48V output for network equipment, 24V output for industrial equipment, and 5-20V output, which is commonly used in consumer devices.
In response to current issues with power shortages, more and more devices—such as cars, data centers, and USB-PD—are switching to high-efficiency 48V power distribution. Then, in addition to GaN, polymer capacitors will be more active.
*Hybrid＝Polymer＋Liquid electrolyte
Known as pioneers of metal composite power inductor technology, Panasonic Industry has undoubtedly made a name for itself - but the industries’ rapid developments and increased demands on the specs of passive components wouldn’t allow any rest on the laurels:
Depending on the area and specific application, the demands are as high and differentiated as never before: From higher currents, better resistance to vibrations, lower losses for specified frequencies up to serving the trend for miniaturization: In the following, we attempt to illustrate the power inductors’ diversification in a brief summary:
1) High Power
As the number of electric components per vehicle is ever increasing, the required currents are increasing accordingly. Since the market introduction of the Panasonic MC series in 2004, the current specification of the ETPQ power choke coils raised steadily. Currently, the ETQP8M***JFA - series in the dimensions of 12x12mm reveals the highest-rated current specification with 53A. Due to the newly developed integral construction, it also comes with very high resistance of up to 30G against vibrational shocks, which is unmatched for metal composite power inductors of that size.
Picture: ETQP8MR68JFA
Panasonic Industry follows the automotive industry’s needs to offer ever smaller and more compact power inductors with ever-higher current capabilities. Based on the innovative design of the ETQP8M***JFA - series, the ETQPAM***JFW - series has been developed with dimensions of 15x15x10mm and current capabilities of up to 73A. This innovative series significantly exceeds the current capabilities of comparable products in the market due to reduced DC-losses and an optimized magnetic flow within the metal core. The ETQPAM***JFW - series is specifically targeted to 48V-DCDC converters which require very high current capabilities - and enables customers to further downsize their systems.
2) Robustness
Since the first developments on a metal composite power inductor for automotive applications started at Panasonic, robustness has been a major topic. As electronic systems became more and more integrated, they got positioned closer and closer to the engines of a vehicle. This of course requires high robustness against vibrational shocks to guarantee long-term mechanical durability. At the time of introduction, the MC series was already a major improvement compared to conventional ferrite inductors with specified robustness of 10G. Over the years, the design and production process of Panasonic power choke coils improved remarkably. This leap in know-how resulted in the development of the ETQP*M***YS* - series, offering industry-leading vibration robustness of up to 50G. It is specifically targeted at ECUs which are situated in the engine itself or mechanical-electrical-integrated ECUs.
Picture: ETQP5MR68YSC
3) Low Power Loss
As another area of research, Panasonic Industry investigates the development of power choke coils with minimal losses. The latest innovation in this area is the ETQ-P3M***HF* - series optimized for frequencies up to 5MHZ. It was specifically developed for power circuits in ADAS applications as well as navigation and telematics systems. Both the magnetic material and the winding technology have been developed in-house at Panasonic Industry, resulting in a compact high precision and high-performance coil, that comes with a convincingly reduced volume ratio of 30% when compared to existing products.
Picture: ETQP3M100HFN
4) Miniaturization
As the electronic industry places a great focus on efficiency, engineers are expected to create products that are thinner, lighter and smaller. The first metal composite power choke coils introduced by Panasonic measured 10x10mm. Over the years, the PCC family got more and more compact members - 8x8mm, 7x7mm, 6x6mm and 5x5mm. Smaller and smaller housings are made possible due to a new innovative production process and are in great demand for ADAS, Radar and Lidar applications.
5) High current (Industry)
With its extensive knowledge about metal composite power inductors, Panasonic Industry also supports industrial and consumer applications. The latest developments are focused on high current applications for Server and GPU accelerators, where the power inductors are designed in DC/DC converters of step-down circuits of CPU or GPU circuits.
The world of electronic innovations is spinning faster than ever - which actually means: as fast as the technology of the installed components allows.
That “one inductor for everything” no longer exists - the demands have become highly diversified, so it pays for every product designer to remain attentive and up to date which specs would be the right ones for their own project.
MLCC problems - and their solution
MLCCs (Multi-layered Ceramic Capacitors) are used in a wide variety of applications but have problems due to inherent characteristics of MLCCs. Some of these problems can be solved by adopting conductive polymer capacitors. In the following, we will show you examples of two solutions.
First problem: The capacitances of MLCCs drop when they are supplied with DC biases or operated under high-temperature and/or low-temperature conditions. This leads to an increase in the number of MLCCs used.
It is a well-known fact that the capacitances of MLCCs drop significantly when DC biases are applied to MLCCs and that the capacitances also drops when the MLCCs operate in high-temperature or low-temperature conditions.
The MLCC shown here in the graphs loses its capacitance by 80% when supplied with a 15 V DC bias voltage, and by about 10% when operating in high-temperature or low-temperature conditions.
Let's assume a case where MLCCs need to have a total capacitance of about 47 µF when supplied with a 15 V DC bias voltage. Taking the above capacitance reduction into consideration, we have to ensure the total capacitance based on the MLCC's nominal capacitance value of 20%. For the case of 22 µF MLCCs indicated in the graphs, the number of MLCCs to be used is calculated as follows.
22 µF × 20% ＝ 4.4 µF 47 µF ÷ 4.4 µF ≅ 10.7
In this example, ensuring the total capacitance the circuit needs, which is 47 µF, requires 10 or more MLCCs each having the nominal capacitance of 22 µF, meaning that the total nominal capacitance amounts to 220 µF or more. The number of MLCCs used can be reduced by adopting a MLCC with a larger capacitance. However, the capacitance of a general chip-type MLCC with a 25 V voltage rating, a 47 µF (maximum) could be used, but it cannot be bigger than that. Therefore, when a larger capacitance is required, several MLCCs with a lower price and smaller capacitance are usually used as a general solution.
Solution: Replacing MLCCs with conductive polymer capacitors whose capacitances hardly fluctuate in response to DC biases or temperature conditions
Basically, different from an MLCC, a conductive polymer capacitor hardly shows a capacitance drop caused by DC biases or temperature conditions. Thus, the ten 22 µF MLCCs, in this example, can be replaced with one 47 µF conductive polymer capacitor. This reduction in the number of capacitors used leads to a reduction in total cost, including packaging-related costs. It is also possible we could even reduce the mounting area.
Here is a specific case of an HDD where a capacitance of about 140 µF is needed for a 12 V bias voltage in order to ensure data backup and safe shutdown of the HDD in a power failure event. To achieve the 140 µF capacitance using 22 µF MLCCs, we need 36 MLCCs, which brings the total nominal capacitance up to 792 µF based on the assumption that each MLCC has its capacitance reduced by about 80% due to DC biases. If we employ conductive polymer capacitors SP-Cap, however, three of them provide 47 µF × 3 = 141 µF, which meets the capacitance requirement. This case reduces the number of capacitors used and the mounting area as well, leading to a reduction in total cost. In addition to the SP-Cap, other conductive polymer capacitors, such as POSCAP, offer the same effect through the approach described above.
Second problem: Screeching noise emission and micro-vibrations
A MLCC deforms (contracts/expands) when a voltage is applied thereupon. This MLCC's characteristic is called inverse piezoelectric effect, which is the reverse of a piezoelectric effect. Applying a DC voltage to the MLCC merely causes it to deform. If the applied voltage has a frequency-controlled amplitude, however, the MLCC contracts and expands cyclically, thus causing the substrate to vibrate. If the frequency of such vibrations is within the audible frequency range, the resulting sound is unpleasant screeching noise. A DC voltage output from an AC adaptor or switching power supply causes a ripple voltage in some cases. If the frequency of the ripple voltage is within the audible frequency range, it may result in emission of a screeching noise.
There is also a case where micro-vibrations, if not creating noise, affect the operation of equipment. We have a case where the micro-vibration of a MLCC mounted on the magnetic head of an HDD causes an error in data reading/recording.
Solution: Replacing a MLCC with a conductive polymer capacitor that exhibits no inverse piezoelectric effect
There are MLCCs (improved MLCCs) configured for suppressing noise emission, which include a MLCC made of a material that hardly deforms, a MLCC with a length-width reverse structure in which its length, i.e., the distance between its electrodes is made shorter than its width, and an MLCC with leads, which are referred to as metal terminals or metal frames. It is true that such MLCCs certainly reduce noise emission and micro-vibrations but do not eliminate them completely.
A conductive polymer capacitor has no inverse piezoelectric effect and therefore causes no noise emission or micro-vibrations. Shown below is an example in which an MLCC, an improved MLCC with metal terminals, and a conductive polymer capacitor are compared regarding noise emission with each other.
Here is an example in which a notebook PC' MLCCs (used as input capacitors in a DC/DC step-down converter for adjusting a voltage from the AC adaptor) cause screeching sound emission. MLCCs with metal terminals are said to be relatively effective as an alternative to ordinary MLCCs. The graph shown here demonstrates that MLCCs with metal terminals reduce the sound pressure of screeching noise. In the graph, a red curve represents ordinary MLCCs while a green curve represents MLCCs with metal terminals.
In this example, we have replaced eight 10 µF MLCCs with metal terminals with one 33 µF SP-Cap conductive polymer capacitor and checked noise emission. Obviously, the SP-Cap caused neither noise emission nor micro-vibrations, providing a perfect solution to the noise emission problem. This is the same outcome as adopting a SP-Cap in the previous case. Using other types of conductive polymer capacitors offers the same effect as described here.
A conductive polymer capacitor has an electrolyte made of conductive polymers, offering low equivalent series resistance (ESR), an excellent high-frequency property, and stable characteristics not dependent on temperature or voltage. Panasonic provides a lineup of various conductive polymer capacitors, putting four types of them on the capacitor market.
| Name/shape |  Aluminum polymer (laminated) |
 Tantalum polymer |
 Aluminum polymer (winding) |
 Aluminum hybrid |
|---|---|---|---|---|
| Major features |
|
|
|
|
Product range
|
|
|
|
|
We have shown two examples concerning problems with MLCCs, which originate from their inherent characteristics, and solutions to the problems, which are provided by conductive polymer capacitors.
In one example, the capacitance drop of MLCCs caused by DC biases and temperature conditions is taken into consideration, which determines the number of MLCCs used so that the required total capacitance is achieved. Because the capacitance of each MLCC is not sufficient, a large number of MLCCs, having a relatively small capacitance, must be provided to achieve the total capacitance. In contrast, conductive polymer capacitors only exhibit minute capacitance fluctuations caused by DC biases and temperature conditions, and some of them have large capacitances. For this reason, replacing MLCCs with conductive polymer capacitors allows a reduction in the number of capacitors used and in the mounting area, thus leading to a total cost reduction.
In another example, we described the solution to noise emission and micro-vibrations that are caused by the inverse piezoelectric effect of MLCCs. While some improved MLCCs suppress noise emission and micro-vibrations to some extent, conductive polymer capacitors, which have no inverse piezoelectric effect, eliminate noise and micro-vibrations completely. Replacing MLCCs with conductive polymer capacitors, therefore, is a perfect solution to the noise emission/micro-vibration problem.
In these examples, a SP-Cap conductive polymer capacitor is described as the typical alternative to an MLCC. Depending on given requirements, conditions, etc., you can choose your optimum alternative from four types of conductive polymer capacitors: SP-Cap, POSCAP, OS-CON, and Hybrid.
Panasonic has web sites that provide detailed data of conductive polymer capacitors and other electronic devices.
■Characteristic viewer
(https://util01.industrial.panasonic.com/ww/utilities/ds/chr-vw/)
The characteristic viewer is a tool with which various characteristics of a selected component are plotted on graphs having a frequency axis, temperature axis, etc. It allows you to easily check component characteristics, such as changes in characteristic values in the working frequency range, and is therefore useful as a component selection tool.
In the case of checking the characteristics of conductive polymer capacitors SP-Cap and POSCAP, using the characteristic viewer, the viewer indicates the frequency characteristics of the impedance |Z|, resistance component ESR, capacitance C, and inductance component ESL of SP-Cap and POSCAP.
Example: EEFSX0D471E4 (SX系列, 2V 470μF, ESR4.5mΩ)
■Simulation Data
(https://industrial.panasonic.com/ww/downloads/simulation-data)
We also offer a web site for downloading simulation data. From this site, you can download frequency characteristic data (PDF), equivalent circuit models (SPICE models), and S parameters for each product number.
Example：EEFSX0D471**(SX系列、2V470μF)
Despite the emergence of alternative capacitor technologies like hybrids, electrolytic capacitors continue to stand out as the optimal choice across various applications. Their enhanced performance, extended lifespan, and cost-effectiveness solidify their position as a top preference among designers. However, the availability of these capacitors is increasingly constrained due to certain manufacturers issuing EOL (end of life) notices, particularly for through-hole technology (THT, also known as plated through-hole, radial lead, or leaded) parts.
Aluminum electrolytic capacitors have a higher capacitance-to-volume ratio compared to ceramic capacitors, offering the advantage of compactness, a pivotal benefit in various scenarios. Commonly utilized for mitigating voltage fluctuations—such as in rectified AC smoothing, noise filtering, and audio frequency amplification—electrolytic capacitors have been the go-to choice. However, the last decade has witnessed the emergence of polymer and hybrid polymer capacitors that present distinct advantages over conventional electrolytic types. These benefits encompass an extended lifespan, elevated maximum working temperature, enhanced stability, reduced equivalent series resistance (ESR), and a safer failure mode.
Despite such advancements, many design engineers still favour straightforward electrolytics. Primarily this is due to their cost-effectiveness, particularly in applications where space constraints aren't an issue. Additionally, certain applications—for example, power supplies—rely on leaded parts, offering cost savings. Although surface mount technology (SMT) might seem dominant, especially in power supplies, the inclusion of magnetic components often necessitates through-hole mounting for mechanical stability. Consequently, PCBs must commonly accommodate both SMT and THT parts, reducing the choice between leaded or surface mount capacitors to component pricing, assuming equivalent performance.
Short video interview: "E-Caps-dead or alive? Panasonic Industry and its continued commitment to electrolytic capacitor technology"
However, concerns have arisen as some manufacturers have issued end-of-life (EOL) notices leaded electrolytic capacitors in specific case sizes. Panasonic Industry takes a different view, and distinguishes itself by considering electrolytic capacitors a core technology. The company continues to invest in research, development, and expanded manufacturing capacity. For leaded through-hole (THT/PTH) devices, Panasonic commits to supplying all case sizes and capacitance values in its portfolio for the foreseeable future.
THT Electrolytic Capacitor
Panasonic's FR and FS series exemplify high-performance leaded electrolytic capacitors. The EEU-FR series, ranging from 6.3 to 100 VDC, offers capacitance values from 4.7 to 8200µF in case sizes from Ø5x11 to Ø16x25mm. These capacitors come with a 10,000-hour lifetime, operation up to 105˚C, low ESR, and robust ripple-current capabilities. Similarly, the EEU-FS series, rated from 6.3 to 100 VDC, delivers capacitance values from 27µF to 10000µF, optimizing space and potentially reducing the required number of capacitors within the same case size.
While through-hole electrolytic capacitors still hold demand, modern designs predominantly employ surface mount (SMT) devices for their smaller form factor and ease of automation. Consequently, most research and development efforts concentrate on SMT components, an area where Panasonic leads.
Panasonic Industry's SMT FH series
A prominent trend involves enhancing capacitor lifespans to align with global sustainability movements. Panasonic, with its GREEN IMPACT initiative, pledges to achieve net-zero CO2 emissions across its operating companies by 2030. This commitment resonates with the vision for 2050, aiming to contribute to society-wide CO2 reductions by promoting energy-saving products and green energy technologies. Longer-lasting components play a pivotal role in sustainable operations, reducing the need for frequent replacements.
Specifically addressing applications, remote metering and small cell base stations necessitate components with extended lifespans due to challenging accessibility and costly downtimes. Panasonic's FH series stands out, offering the longest lifetime for surface mount electrolytic capacitors in its class. Ranging from 6.3 to 100V, these capacitors provide capacitance values from 10 to 680µF in case sizes of Ø6x7.7h to Ø10x10mm, with a 10,000-hour lifetime at 105°C—3000 hours (>40%) longer than most competitors. Competitors that match the lifetime cannot offer equivalent capacitance or temperature ratings, showcasing Panasonic's superiority. Additionally, the FH series minimizes ESR and boasts high ripple-current ratings, aligning with Panasonic's commitment to superior performance across its electrolytic capacitor range.
Thanks to substantial ongoing investments, Panasonic Industry has not only increased its electrolytic capacitor production capacity by 10% but also reduced lead times. Continual performance enhancements, particularly in lifespan, capacitance-to-size ratio, temperature ratings, and ESR, signify the company's dedication to this product sector. While some competitors exit the industry, especially concerning through-hole parts, Panasonic remains committed, ensuring the wide availability of top-performance parts. As far as Panasonic is concerned, electrolytics are undoubtedly here to stay.
As developers and engineers, you are familiar with the challenges that arise and understand the power when metal enclosures or housings shield or disrupt a decent flow of BLE data throughput.
Join us for the following video on a short investigative journey as we uncover the complexities of BLE performance when faced with metal enclosures. Learn more about Panasonic Industry’s PAN1770, a BLE® transceiver module equipped with an external uFL connector.
We don’t want to spoil the exact test results - but watch the PAN1770's readiness for an external antenna triumph over this challenge, and might be the solution for whatever you’re up to with your metal-shielded application concepts!
You need an external antenna? Please think about the effects on regulatory requirements! While PAN1770 integrates the Nordic Semiconductor nRF52840 it includes a uFL connector allowing to mount different antenna types featuring different antenna gains. The current certification includes a terminal antenna from Pulse (W1030) in combinaton with a TE connectivity cable.
Further antennas and antenna types can be added on request.
| PAN1770 | PERFORMANCE CHARACTERISTICS |
|---|---|
| RF category | Bluetooth® 5.3Low Energy, IEEE® 802.15.4, NFC |
| Software/profile | Nordic Connect SDK |
| Used IC | nRF52840 |
| Rx sensitivity | -95 dBm @1Mb/s,-103 dBm @125kb/s |
| Tx power max | +8 dBm |
| Antenna option | uFL Connector |
| Size (l x w x h) [mm] | 15.6 x 8.7 x 2.0 |
| Power supply [V] | 1.7 to 5.5 |
| Power consumption Tx | 4.8 mA @0dBm (3.3V) |
| Power consumption Rx | 4.8 mA (3.3V) |
| Power consumption sleep | <1 µA |
| Interfaces | GPIO, UART, QSPI, I2C, I2S, PDM, ADC, PWM, NFC-A, USB2.0 |
| Microcontroller | ARM® Cortex®-M4F |
| Memory | 1MB Flash and 256kB RAM |
| Speciality | Integrated 32kHZ Crystal |
| Certification | CE RED / FCC / ISED / Wirepas |
| Operating temperature | -40 to +85 °C |
| Standard packaging QTY | 1500 pcs |
Important to consider while adding an external antenna: The system output power.
Different regions or countries allow different output power from a regulatory point of view:
The system output power consists of module output power, cable loss and antenna gain.
In the setting shown above, a maximum system output power of 9,85dBM can be achieved while still complying with european CE RED regulation.
For the end product certification, Panasonic Industry provides all required certification documents and test reports, e.g. for Radio, EMC, Safety and Health.
Learn more under:
PAN1770 (nRF52840) | Panasonic Industry Europe GmbH
Revision 2 - Wireless Connectivity Development Hub (panasonic.de)
As the world moves towards making more eco-friendly responsible choices, the demand for sustainable and renewable energy has driven consistently high growth in the solar inverter market.
A solar inverter (also called a photovoltaic or PV inverter) converts direct current (DC) into alternating current (AC) and is widely used in solar photovoltaic power generation systems.
Solar inverters available today are generally divided into three types: central inverters, string inverters and micro-inverters.
In this blog, we would like to introduce Panasonic's film capacitors - one of the fundamental passive components in electronic circuits – and show how they can contribute to optimizing the design of string inverters.
Regardless of the type of solar inverter, the key requirements are high efficiency, high reliability and input voltage with a wide range of capacitance values. This contribution of attributes is exactly why Panasonic's various metallized PP film capacitors can play an essential role in a solar inverter’s circuit design as they feature a large current handling ability, high reliability and proven safety performance. Our capacitors are used for input & output filtering, EMI suppression, snubber and DC link circuits.
Figure 1. Simple diagram of a solar inverter circuit
On the input side of the primary DC filter circuit ① as well as for the DC-link circuit ⑤, DC-rated EZPV series film capacitors provide DC filtering. Parts with voltage ratings of up to 1300VDC and a wide capacitance range of up to 110μF are available as one single component; both 2-pin and 4-pin terminal solutions are available.
On the input side of the DC/DC converter circuit, as well as in snubber circuits (② + ④ in Figure 2), DC-rated ECWFD series (coating type), ECWFE and ECWFG (box type) film capacitors, are ideal solutions for smoothing. Various rated voltage values are available from 450VDC up to 1100VDC. The capacitance range stretches from 0.01μF up to 12μF. Excellent safety performance (thanks to a built-in fuse function), high-frequency characteristics and high ripple current capacity help these three film capacitor series devices to optimize the high voltage circuit of a solar inverter. AC-rated EZPQ series film capacitors with a higher rated voltage range of 250VAC to 600VAC are also available. This industrial-grade AC capacitor can be used as an output filter.
Figure 2. Structure of patterned metallization (fuse function)
Considering that reliability - especially in humid conditions - is critical for solar inverters which are used outdoors, Panasonic has developed its own enclosure sealing technology and 100% aluminium vapour deposition processes which enable our film capacitors to achieve high humidity resistance.
Figure 3. 100% Al for metallization & vacuum control for sealing
Figure 4 below, shows the key attributes of Panasonic's film capacitors when used in solar inverters:
Figure 4. Features of Panasonic metallized PP film capacitors
We are committed to high output, high safety and high reliability, so Panasonic's film capacitors can help optimize your solar inverter design.
Panasonic OS-CON conductive polymer solid aluminium capacitors play a major role in the optimization of solar inverters. To efficiently generate energy from the sun, the solar panel must absorb energy from the sun continuously as the earth rotates. By detecting and tracking the live position of the sun and adjusting the angles of the panel to ensure that it always faces the sun the solar energy harvest can be maximized.
Conventional solar inverters have a centralized power conditioner that controls the entire module.
Figure 5: Centralized Power Conditioner
Figure 6: Micro-Inverter
New requirements that these micro-inverters demand include a long lifetime of 5-10 years, space-saving, and cost-reduction. OS-CON capacitors satisfy these new requirements.
Figure 7: Solar Inverter Circuit Example
A single OS-CON can replace seven MLCCs in a micro-inverter design, reducing PCB space by 31%. Another benefit of using OS-CON is that capacitance is not reduced, unlike MLCCs which cause a reduction of capacitance due to DC-Bias.
Figure 8: MLCC Replacement with OS-CON
Aluminium electrolytic (lytic) capacitors can also can be replaced by OS-CON capacitors, increasing the life of the micro-inverter. Using OS-CON capacitors in this example also saves space, since two OS-CONs can replace three lytics.
Figure 9: OS-CON can replace electrolytic capacitors
Many resistors are used in a solar inverter circuit. Current requirements focus on high voltage, high efficiency for energy saving, and long lifetime. For the resistor, this means high reliability with long lifetime, high voltage-withstand capability and high accuracy. Panasonic has a variety of resistor families that can be employed in solar inverters applications.
Figure 10: Resistor arrangement in solar inverters, (Resistor position / Role / Recommend Panasonic PNs / R1, R2 / Regulator, Voltage monitor / ERJP series (Thick Film R) / R3 / Gate driver resistor / ERJH series (Thick Film R)
For the regulator and voltage-sense, ERJP series resistors can be used thanks to their high power specifications and superior anti-surge and anti-pulse-withstand performance compared to standard metal film resistors. Thanks to Panasonic's unique resistive element trimming shape, it is possible to achieve higher power in smaller chip size and improved overload characteristics.
Figure 11: Table showing Power Vs Case Size
Figure 12: Space Saving and Performance
Figure 13: Surge Distribution
Gate driver resistors are normally required to have a high power capacity and to be able to survive the high temperatures caused by heat generated within the IGBT and inverter. ERJH series resistors can achieve high heat resistance when exposed to a harsh thermal environment, reaching maximum operating temperatures of 175℃ and rated operating temperature of 105℃. Additionally, improved thermal shock resistance is achieved thanks to high-heat-resistant materials and soft electrode materials, thereby reducing the risk of solder cracks.
In the motor drive control unit, resistors are required for amplifier and feedback circuits. Key requirements are high reliability, long life and stable resistance values. Panasonic's thin film resistor ERA*A series (High-reliability type) and ERA*V/K series (High stability and reliability type) can contribute to obtain high accuracy. ERA*V/K resistors reduce solder joint cracking by adding a resin layer on the underside and allow to achieve high precision and a longer life than current devices thanks to improvements in the construction and material. Also, ERA*V/K series structure guarantee sulfuration resistance. These improvements make them suitable for the harsh operating conditions that micro-inverter applications routinely encounter.
Figure 14: Anti-Solder Joint Cracks
Solar inverters need inductors that are capable of handling high voltages and large currents in the main circuit. Pansonic inductors, thanks to their high-quality design, can meet these requirements ensuring a stable inductance value during lifetime. In addition to the inductor's role in the primary circuit, power inductors are also used in the auxiliary circuit for the controller and gate drivers, where digital logic provides critical controlling and monitoring functions for solar energy harvesting systems. Since high switching speeds are employed and operating conditions can be harsh, high-performance power inductors such as the Panasonic Metal Composite ETQP family are required.
As a pioneer of metal composite power inductors, Panasonic offers a broad line-up of power inductors that offer the highest efficiency and reliability.
Figure 15: DC/DC Converter
Figure 16: DC/DC Circuit Diagram
One of the most important requirements of a power inductor for a DC/DC converter is high power efficiency. Inverter suppliers are facing tough demands for reduced inverter system size and higher efficiency. So the challenge for the inductor supplier is to provide an inductor at a small size with high current capability and minimal heat dissipation. The Panasonic ETQP high-performance inductor series (ETQP*M***Y**) exactly fulfils this requirement with a broad line-up that covers sizes from 5x5mm to 10x10mm, supporting currents of up to 39.7A with an inductance range of 0.33 – 100µH. The high efficiency is a result of both low AC resistance and low DC resistance, enabled by the use of a unique magnetic material with high permeability, as well as a unique wire winding structure. As a result, ETQP*M***Y** inductors support a higher total system efficiency.
Figure 17: Efficiency
A general trend in the electronic industry is the standardization and modulization of systems. However, this means that passive components suppliers need to provide products which scale over a broad range of requirements in regard to electrical power capability. The high current capability of parts such as the ETQP series (ETQP*M***Y**) greatly supports the standardization of solar inverter systems, as they support a wider range of current flow, depending on the requirement of the individual system.
Panasonic metal composite power choke coils not only exhibit stable inductance over current but are also stable with temperature, as you can see in the graph below. This is in stark contrast to ferrite inductors, where the inductance value is influenced by the temperature of the inductor, requiring great effort from design engineers to qualify the component for different temperature ranges when used in solar inverters. With stable temperature behaviour, much less time is required for qualification, which reduces development costs and time.
Figure 18: Temperature Stability
Another area within a solar power inverter that requires a power inductor is the gate driver of the FET that transforms the DC current of the battery to the 3-phase sine wave, which is fed into the power grid. The biggest advantage of the Panasonic metal composite power inductor is the stability of its inductance value over its lifetime. While the inductance of a ferrite inductor will vary with age, the metal composite material is free from any effects of ageing, helping the inverter manufacturer to guarantee a system that functions over its entire specified lifetime. Panasonic specifically recommends the ETQP LP series (ETQP*M***KV*) as the most cost-efficient metal composite inductor solution for the gate driver of an inverter.
As is the case with the DC/DC converter, the power inductor of the gate driver circuit also greatly benefits from a stable temperature behaviour of the inductance value. This attribute also helps to reduce the development and qualification time of the gate driver circuit, as engineers do not need to consider a fluctuation of the inductance value of the inductor, which is not only influenced by the power loss of the inductor itself but also by the heat dissipated by surrounding components.
As already stated, designers of inverter systems are under constant pressure to make their systems smaller and more efficient. Compared to ferrite inductors, metal composite inductors have a much higher energy density, which leads to a size reduction of 30% - 50% for comparable current specifications. So a designer can save PCB space or run at higher currents simply by using Panasonic's metal composite inductors rather than traditional ferrites.
Figure 19: Weight vs Volume
Despite the tense situation on the semiconductor markets for the past two years, Panasonic Industry has invested heavily in stocks - and now reports that, for instance, the Bluetooth® Low Energy modules from the PAN1780 family are available in exceptionally short lead times now.
A lead time as short as approximately 16 weeks for a comprehensive range of top-notch BLE modules can be currently considered attractive - the company’s range of Nordic Semiconductor-based BLE wireless modules comprises the flagship PAN1780 as well as it’s siblings PAN1770, PAN1781 and PAN1782. Each of them is coming with tailored specs and a well thought-out price-performance ratio – meeting the most relevant application requirements:
PAN1780 is a Bluetooth® 5 Low Energy Module based on the Nordic nRF52840 single-chip controller coming with 1MB Flash/256kB RAM and integrated chip antenna
PAN1770 is the antenna-less sibling of PAN1780 – and provides an uFL connector for applications with radio-unfriendly housings
PAN1781 comes with the nRF52820 single-chip controller inside – and renders with its 256kB Flash/32kB RAM an ideally cost-effective solution for compact applications.
PAN1782 is the latest member in Panasonic’s BLE module family – and with 512 kB Flash/128 kB RAM memory the perfect trade-off between performance and price.
So, rapid implementation of promising connectivity application projects do not longer need to fail due to unavailable components - at least in terms of Panasonic's state-of the-art BLE modules in a wide range of variations.
Everyone knows that heat is a system killer. A general rule of thumb is that the life-time of a device decreases by 50 percent each time when the temperature rises an additional 10 degrees Celsius. To look at it from another angle, the MTBF (meantime between failure) will, on average, double if the operating temperature is lowered by 10 degrees Celsius. System performance and efficiency play crucial roles here.
All this – as we have said – is well known. Good design will see sensitive or heat-producing components or system elements mounted on, or close by, heatsinks and fans or directly attached to them. Even if the path is optimal when the device is new, it can degrade such that eventually the process of removing heat becomes ineffective. This article looks at a variety of ways to achieve good interfacing between heat sources and heatsinks while focusing on solutions for power modules, including a new material that solves many of the challenges faced by design and production engineers.
When cooling heat-generating components using heatsinks, gaps can occur between the two adjoining surfaces, resulting in air pockets which increase the thermal resistance such that efficient cooling cannot be achieved. Therefore, these gaps must be filled using a thermal interface material (TIM) with a low thermal resistance.
Types of thermal interface material (TIM)
Around a long time, thermal grease is the most common and cheapest form of TIM. They are applied between heating elements and heat sinks. However, it is difficult to apply them evenly and repeatedly, and there is also an issue of long-term reliability, since they can dry out and lose efficacy.
Phase change materials (PCMs) are somewhat more costly, but often deliver better performance than standard silicon-based thermal grease. They feature reduced contact thermal resistance due to improved adhesion caused by the softening at high temperatures. Although they are easy to handle, the materials are costly and have the issue of long-term reliability.
Thermal conductive sheets are made from a TIM such as silicon, elastomer or graphite. Sheets are sandwiched between the heating elements and heatsinks; they are easy to handle but, due to their hardness, they require pressure to achieve adequate contact.
To save space, more and more power module are positioned vertically. With the power module in a vertical position, thermal greases, or even PCMs, are likely to discharge due to the gravitation accompanying temperature changes, leading to a medium-to-long-term degradation in performance. This effect occurs especially when the greases dry out, therefore many customers choose the thermal conductive sheet solution.
Key requirements for thermal interface materials
There are three main requirements for TIMs. First, they must have a low thermal resistance. This means they should achieve adequate contact in order to also allow for any warping or rough surfaces. Second, TIMs must have stable characteristics over the life of the equipment, and require no maintenance required. Lastly, they must be easy to attach and remove from the heatsink and power module without any significant investment in production in order to be simple to change in the field as well.
Graphite Sheet TIM
Pyrolytic, highly oriented graphite sheets are made of graphite with a structure that is similar to a single crystal These sheets are produced from polymeric film using a heat de-composition process. The hexagonal structure of the graphite is uniformly arranged in a horizontal 2D position as shown in Figure 1.
Figure 1: Hexagonal mono-layer of the graphite sheet.
In applications like general power inverters, solar inverters or EV charging stations that use power modules, thermal grease is usually utilized to fill the voids caused by distortion and roughness of the contacting surface. Over time, the grease dries out or is “pumped out” as a result of temperature changes and therefore needs replacing. This is a costly exercise, as either the entire system has to be exchanged or a a technician must make a field call and remove the old grease, clean everything, apply new grease and re-assemble the system.
With pyrolytic graphite sheet technology, such as Panasonic’s GraphiteTIM, the sheet has been designed exclusively to act as a thermal conductor, replacing the conventional grease or PCM. Graphite TIM is highly compressible and thus fits well to the uneven surfaces, reducing thermal contact resistance which results in high heat dissipation, high reliability and easy handling (Figure 2).
Figure 2: Standard assembly of a IGBT/SiC module with TIM and heatsink
GraphiteTIM characteristics
As opposed to other thermal interface materials, GraphiteTIM diffuses heat not only in Z direction but also distributes heat across the X-Y plane, thereby delivering a much better cooling effect (Figure 3).
Figure 3: Heat distribution across the plane and dissipation at the heatsink.
Typical characteristics of the Panasonic GraphiteTIM material are shown in Table 1.
Table 1
Compressibility and thermal resistance
Panasonic’s GraphiteTIM is considerably softer than comparable graphite sheet materials. Because of its high compressibility it can fill voids more effectively. Generally, standard thermal graphite sheets have a compression rate of 20%, while graphite TIM offers compression rates up to 60%. To achieve this high compression, the contact pressure should be 300 kPa to 600 kPa (Figure 4a and 4b).
When adequate pressure is applied, the initial thermal resistance of GraphiteTIM drops well below the level of common thermal greases. (Figure 5).
Figure 4a: Impact of compressibility on the contact
Figure 4b: Compressibility as a function of the contact pressure
Figure 5: Thermal resistance from GTIM and thermal greases as a function of the contact pressure
Reliability
The more reliable the thermal interface material is, the longer the life-time and robustness of the application due to reduced thermal stress on it. Long-term tests demonstrate that the performance of GraphiteTIM remains constant after many thousand cycles, while the effectiveness of thermal pastes diminishes after just a few hundred cycles. (Figure 6).
Figure 6: Long-term tests of GraphiteTIM and thermal grease
Ease of handling
Figure 7 compares the application of thermal greases and PCMs with GraphiteTIM. Whereas positioning the sheet can be accomplished in one step, using thermal paste involves multiple steps, including preliminary treatment, application, drying and cleaning.
Figure 7: Application process for GTIM and thermal pastes
Panasonic offers three different thicknesses of GraphiteTIM to bridge the gap between heat source and heat sink. The optimal sheet thickness mainly depends on three parameters:
Table 2 shows Panasonic’s recommendations based on these parameters.
Table 2: Sheet thickness recommendation based on size of the module and contact pressure
Panasonic Industry offers GraphiteTIM in 56 standard shapes that are compatible with various industry-standard power modules including products that match modules from Semikron, Hitachi, Fuji, Infineon and Mitsubishi, as detailed in the GraphiteTIM selector tool at https://industrial.panasonic.com/ww/soft-pgs-cross.
Please also refer to the detailed P/N list in the attached excel.
GTIM shapes matching modules from Infineon and Semikron.xlsx
Custom shapes are also available.
Communications service providers are contributing intensely to large and hyper-scale data centres to deliver data processing, content, and communications services. The applications delivering these services must have access to high-speed storage and networking, be secure and run in a virtualized environment based on software-defined networking (SDN). Encryption, virtualization software, load balancing, deep packet inspection (DPI) and packet processing all require numerous CPU cycles and can tie up many processor cores, reducing the number of cores accessible for applications.
Smart network interface cards (NICs) can offload IP packet processing and other processing that would otherwise slow down the CPU. Smart NICs can be used to accelerate the processing power of virtual server environments. By installing smart NICs, communications service providers can deliver significantly better revenue-earning services with a small increase in investment.
Smart NICs can be based on an ASIC, FPGA or System on a Chip (SoC) and there are specific advantages and tradeoffs to each. Regardless of which smart NIC we are looking at, it needs to deliver high performance and reliability. As the result, they require passive components that can deliver these benefits.
Panasonic Industry Polymer capacitor technologies with large capacitance and low ESR help DC/DC ICs to stabilize the power rail voltage at large fast load current transient events.
Exemplary Visualization of Smart NIC
SP-Caps (Panasonic Conductive Polymer Electrolytic Capacitors) are great choices for today’s high current processors like CPU, GPU, FPGA, ASIC, DDR memory and other emerging high-performance ICs, to support their very strict (fast and large) load transient conditions. The key enablers are GX’s (1) 3mΩ SR which is the lowest value in Polymer type, and (2) 330µF-560µF capacitance values which are larger than those of ceramic capacitors, and more stable with voltage and temperature. GX Series come with 7.3x4.3mm area + 2mm height package (=suitable on PCB’s backside), and available with 2 terminals (GX-R) and 3 terminals (GX-L). For Higher switching frequencies or reducing ceramic capacitor count, GX-L will be the best choice due its low ESL.
In addition, TPE series of POSCAP (Panasonic Conductive Polymer Tantalum Solid capacitors) with low ESR in miniaturized cases and TQC series by offering voltage range from 16V to 35V are other alternatives for Smart NICs. Manufactured by Panasonic using a unique process, POSCAP is based on sintered tantalum as the anode system and a highly conductive polymer on the cathode side. In addition to a low ESR, the extremely slim and small POSCAPs are the reliable choice for high-frequency applications, mainly because of their high heat resistance.
Finally, "OS-CON" (Panasonic Conductive Aluminum Solid capacitors) is an aluminum solid capacitor with a high conductive polymer. OS-CON acquires low Equivalent Series Resistance (ESR), excellent noise reduction capability and frequency characteristics. In addition, OS-CON has a long-life span and its ESR has little change even at low temperatures since the electrolyte is solid. Our new series "SVT" is surface mount type (vertical), low ESR, large capacitance and high ripple current with a better endurance performance that is 125℃ 2,000 hours, which enables use in high-reliability applications such as servers, base stations, switch router and power supply.
As this illustrates, Panasonic Industry offers an unrivalled range of Polymer Cap technologies – and hence is worth a closer look, when it comes to identifying reliable high-performance solutions for next-gen application designs.
.jpg-100x100x2.jpg?sv=2016-05-31&sr=b&sig=5M4L4wKWol6LCXSfgRCCb6UULvkWcKI4KOO6F03SEL0%3D&se=2024-12-05T23%3A59%3A59Z&sp=r&_=rzJVlBRGGje1Xcs5/wkBMA==)
...that the demand for Multilayer Ceramic Chip Capacitors (MLCCs) is growing: Applications in the field of consumer electronics, data processing, telecommunications and many others have not only significantly intensified MLCC market growth – they even led to an industry-wide shortage for the recent years.
All those parameters contributed to more and more OEMs started looking for alternatives to eventually replace MLCCs with different capacitors – also in anticipation of an increasing demand due to 5G.
Some relevant MLCC alternative can be found within Panasonic Industry’s portfolio: As leading manufacturer of Polymer Capacitors with a long design-in expertise, the SP-Caps and OS-CON are as well worth a closer look as POS-CAP Tantalum Polymer Capacitors or the manufacturer’s Polymer Hybrid Aluminum Electrolytic Capacitor technologies.
For conductive Polymer capacitors, the fields of application have remarkably broadened. The Polymer capacitor (as well as conventional aluminum electrolytic capacitors) stands out with large capacitance figures and excellent bias characteristics that are clearly outperforming multilayer ceramic capacitors.
Panasonic Industry Polymer capacitors already have been proven as a highly relevant alternative for customers seeking to save PCB space and money.
Those Polymer-based capacitors offer a performance edge over conventional electrolytic and ceramic capacitors when it comes to:
• Electrical characteristics
• Stability
• Longevity
• Reliability
• Safety
• Life cycle cost
The various Polymer and hybrid capacitors have very specific advantages and benefits in terms of their ideal voltages, Low ESR, operational conditions and other application requirements.
Including the hybrid ones, there are basically four main varieties of Polymer capacitors. Each of them comprises different construction, electrolytic and electrode materials, packag¬ing and application targets. Let us have a brief overview:
Using a conductive Polymer as the electrolyte and an aluminum cathode, the distinguishing electrical characteristic of these Polymer capacitors is their extremely low equivalent series resis¬tance (down to 3mΩ), which is among the lowest in the industry. SP-caps cover a voltage range from 2–6.3V and offer capacitances between 2.2–820μF. Packaged in a molded resin as compact SMD, these layered Polymer capacitors come in a low pro¬file. As a result of the electrical and form factor characteristics, they suit a variety of handheld electronic devices or other applications that require a low-profile capacitor that will not interfere with a nearby heat sink.
OS-CON caps are also based on conductive Polymers and aluminum, but they have a wound foil structure. The wound Polymer capacitors cover a wider range of voltages and capacitance values than other types of Polymer capacitors. Voltages extend from 2.5 to 100V, while capacitances run from 3.3 to 2,700μF. In addition, their long life time span is one of the factors that they are preferred to be used for servers and base stations. For example, SVPT series with 20,000 hours of life time at 105°C is a unique solution for such applications.
These types employ a conductive Polymer as the electrolyte and have a tantalum cathode. They span voltages from 2 to 35V and capacitances from 3.9 to 1,500μF. They also convince with a low ESR, with some of our POSCAP capacitors exhibiting ESR values as low as 5mΩ. Packaged in a molded resin case, the tantalum Polymer capacitors are among the most compact options available on the market. Though compact, a wide range of sizes is available for this capacitor type.
Hybrid capacitors consist of a combination of a liquid and conductive Polymer to serve as the electrolyte and aluminum as the cathode. The Polymer offers high conductivity – and a correspond¬ingly low ESR. The liquid portion of the electrolyte, meanwhile, can withstand high voltages and provide higher capacitance rat¬ings due to its large effective surface area. The hybrid capacitors offer a voltage range from 25 to 80V and capacitances between 10 and 1000μF. At 8 to 120mΩ, ESR values for hybrids are higher than other types of Polymer capacitors, but still very low considering the higher power applications they address.
It's not only the industry-wide MLCC shortage: Panasonic Industry Polymer caps stand out with excellent specs and characteristics that makes them outperform conventional MLCCs ion several regards.
The MLCC exhibits strong capacitance dependence on DC bias due to ferroelectric dielectric materials used for MLCCs. Polymer ca¬pacitors have no such problem and remain stable over time. This specific advantage allows a significantly lower part count using Polymer instead of MLCCs – apparently saving precious PCB space, costs and steps during production process.
This figure illustrates typical temperature characteristics. The curve changes for MLCCs in various ways within the tolerance range of each product. For Polymer capacitors the capacitance is growing in parallel to the increase of temperature. The temperature characteristics of MLCCs differ according to the dielectric type, but all of them suffer aging failure by exhibiting temperature dependency and require lower operating temperature. Ceramic capacitors are brittle and sensitive to thermal shock, so precautions need to be taken to avoid cracking during mounting, especially for high-capacitance large MLCCs. Typically, ceramic capacitors reveal a temperature range from -40°C to 85°C, respectively 125°C, while the capacitance varies about from +5% to -40%, being in the optimal range around a low temperature of 5 to 25°C. Also in terms of density, field stress and temperature – which is currently still limited to 125°C – Polymer capacitors have great development potential to achieve higher ratings on density, field stress and temperature (yet currently limited to 125°C) due to their working mechanism and dielectric materials advancement, yet higher dielectric constant Polymers enable a higher energy density.
A MLCC deforms – meaning contraction or expansion - when exposed to voltage. This MLCC's characteristic is called inverse piezoelectric effect - the reverse of a piezoelectric effect. A DC voltage output from an AC adaptor or switching power supply causes a ripple voltage in some cases. If the frequency of the ripple voltage is within the audible frequency range, it may result in emission of a screeching noise. A conductive Polymer capacitor has no inverse piezoelectric effect and therefore does not cause any noise emission or micro-vibrations.
Stable Capacitance: The figure on the left shows the change in capacitance over a wide frequency range for different technologies. It clearly shows that Polymer capacitors exhibit very similar performance to multi-layer ceramic capacitors.
Cracks in ceramic surface mount technology (SMT) components limit assembly reliability and yields. These cracks manifest themselves as electrical defects: intermittent contact, variable resistance, loss of capacitance and excessive leakage currents. That is why MLCCs are exposed to different reliability tests including thermal shock, board flex (bending), and biased humidity tests, etc., depending on the targeted applications. Among the reliability tests, the board flex test evaluates the mechanical resistance to cracking when MLCCs are subjected to bending stress on the printed circuit board (PCB) that the MLCC is soldered on. The bending of PCB can occur frequently during/between manufacturing steps and during operation under temperature variations. Flex cracking is due to excessive circuit board flexure. Ceramics are strong in compression but weak in tension. Thus, when a soldered MLCC experiences excessive board flex, a crack is easily generated in the element. A flex crack can cause an electrical conduction between opposing internal electrodes. It is also possible that a fail open can progress to a fail short with continued product usage. If a crack on a capacitor element progresses to a short circuit failure, it may cause problems such as heat generation, smoking, or ignition; therefore, it is indispensable to take measures against them, particularly in equipment where reliability is essential.
Most ceramic capacitors have a fairly high voltage rating. If the capacitor experiences a voltage between its terminals higher than its rated voltage, the dielectric may break down and electrons will flow between the thin metal layers inside of the capacitor, creating a short. Luckily, most ceramic capacitors are built with a hefty safety margin and do not experience any sort of catastrophic failure (such as exploding). However, the rule of thumb dictates that you should derate ceramic capacitors by 50% to 90% depending upon series, voltage and temperature, which means that if you are expecting to have a maximum of 5V between the capacitor’s leads, then you should use a capacitor rated for 10V or more. On the other hand, no derating needs to be considered for Polymer capacitors and normally they can withstand 15-25% surge voltage as well.
The range of Polymer caps as MLCC alternatives is various and comprehensive – there are specific types for specific requirements. What they all have in common, however, is that they are a contemporary choice in terms of electrical performance, reliability, durability and safety - and not least when looking at the overall lifetime cost.
Or to put it even more simply: Polymer caps are not only a good alternative in case of supply shortages of other products, but are actually the first choice for the design process of modern applications.
