Op Amps I: Low Power Op Amps
The element14 Essentials of Low Power Op Amps covers the fundamentals of operational amplifiers with a special emphasis on ultra low power op amps for battery-powered applications. To extend the knowledge covered in the main module, this supplementary guide discusses the types of related components used in op amp circuits.
Micropower
The LMV551 is a high-performance, low-power operational amplifier implemented with TI's advanced VIP50 process (See Section 6.1). It features 3 MHz of bandwidth while consuming only 37 µA of current per amplifier. It is unity gain stable and is designed for ultra-low power applications requiring a wide bandwidth. It has a rail-to-rail output stage and an input common mode range that extends below ground. It has an operating supply voltage range from 2.7 V to 5.5 V. These amplifiers can operate over a wide temperature range (-40°C to 125°C), making them ideal for sensor and portable instrumentation applications. It is packaged in an ultra tiny 5-Pin SC70 and 5-Pin SOT-23 package.
Specified 3-V and 5-V Performance
High Unity Gain Bandwidth 3 MHz
Supply Current (Per Amplifier) 37 µA
CMRR 93 dB
PSRR 90 dB
Slew Rate 1 V/µs
Output Swing With 100-kΩ Load 70 mV From Rail
Total Harmonic Distortion: 0.003% at 1 kHz, 2 kΩ
The LPV511 is a micropower operational amplifier that operates from a voltage supply range as wide as 2.7 V to 12 V with ensured specifications at 3 V, 5 V, and 12 V. The LPV511 exhibits an excellent speed to power ratio, drawing only 880 nA of supply current with a bandwidth of 27 kHz. These specifications make the LPV511 an ideal choice for battery-powered systems that require long life through low supply current, such as instrumentation, sensor conditioning and battery current monitoring. The LPV511 has an input range that includes both supply rails for ground and high-side battery sensing applications. Its output swings within 100 mV of either rail to maximize the signal’s dynamic range in low supply applications. The LPV511 is fabricated on TI’s advanced VIP50C process. The LPV511 is available in the space-saving SC70 package, which makes it ideal for portable electronics with area-constrained PC boards.
Wide Supply Voltage Range: 2.7 V to 12 V
Slew Rate: 7.7 V/ms
Supply Current: 880 nA
Output Short-Circuit Current: 1.35 mA
Rail-to-Rail Input
Rail-to-Rail Output: 100 mV from Rails
Bandwidth (CL = 50 pF, RL = 1 MΩ): 27 kHz
Unity Gain Stable
The LMC6442 is ideal for battery powered systems, where very low supply current (less than one microamp per amplifier) and Rail-to-Rail output swing is required. It is set up for 2.2V to 10V operation. At 2.2V supply, the LMC6442 is ideal for single (Li-Ion) or two cell (NiCad or alkaline) battery systems. The LMC6442 is designed for battery powered systems that require long service life through low supply current, such as smoke and gas detectors, and pager or personal communications systems. Very low (5 fA, typical) input bias current and near constant supply current over supply voltage enhance the LMC6442's performance near the end-of-life battery voltage. Unity gain can be used with a simple compensation circuit, which also allows capacitive loads of up to 300 pF to be driven.
(Typical, VS = 2.2V)
Output Swing to Within 30 mV of Supply Rail
High Voltage Gain 103 dB
Gain Bandwidth Product 9.5 KHz
Ensured for: 2.2V, 5V, 10V
Low Supply Current 0.95 µA/Amplifier
Input Voltage Range −0.3V to V+ -0.9V
2.1 µW/Amplifier Power Consumption
Stable for AV ≥ +2 or AV ≤ -1
NanoPower
The TLV7031 is a single-channel, low-voltage, nanoPower comparator. It offers an excellent combination of speed and power, with a propagation delay of 3 µs and a quiescent supply current of 335 nA. The benefit of fast response time at nanoPower enables power-conscious systems to monitor and respond quickly to fault conditions. With an operating voltage range of 1.6 V to 6.5 V, it is compatible with 3-V and 5-V systems. It also ensures no output phase inversion with overdriven inputs and internal hysteresis, so engineers can use this family of comparators for precision voltage monitoring in harsh, noisy environments where slow-moving input signals must be converted into clean digital outputs. It's available in an ultra-small, leadless package measuring 0.8 mm × 0.8 mm as well as standard 5-pin SC70 and SOT-23 packages, making them applicable for space-critical designs like smartphones, smart meters, and other portable or battery-powered applications.
Ultra-Small X2SON Package
(0.8 mm x 0.8 mm x 0.4 mm)
Tiny 5-Pin SOT-23 and SC70 Packages
Wide Supply Voltage Range of 1.6 V to 6.5V
Quiescent Supply Current of 335 nA
Low Propagation Delay of 3 µs
Rail-to-Rail Common-Mode Input Voltage
5-mV Internal Hysteresis
Push-Pull Output (TLV7031)
Open-Drain Output (TLV7041)
No Phase Reversal for Overdriven Inputs
-40°C to 125°C Operating Temperature
The LPV821 is a single-channel, nanopower, zero-drift operational amplifier for “Always ON” sensing applications in wireless and wired equipment where low input offset is required. With the combination of low initial offset, low offset drift, and 8 kHz of bandwidth from 650 nA of quiescent current, the LPV821 is the industry’s lowest power zero-drift amplifier that can be used for end equipment that monitors current consumption, temperature, gas, or strain gauges.
The LPV821 zero-drift operational amplifier uses a proprietary auto-calibration technique to simultaneously provide low offset voltage (10 µV, maximum) and minimal drift over time and temperature. In addition to having low offset and ultra-low quiescent current, the LPV821 amplifier has pico-amp bias currents which reduce errors commonly introduced in applications monitoring sensors with high output impedance and amplifier configurations with megaohm feedback resistors. The device is EMI hardened to reduce system sensitivity to unwanted RF signals from mobile phones, WiFi, radio transmitters, and tag readers. The LPV821 zero-drift amplifier operates with a single supply voltage as low as 1.7V, ensuring continuous performance in low battery situations over the extended temperature range of -40°C to 125°C. The LPV821 (single) is available in industry standard 5-pin SOT-23.
Quiescent Current: 650 nA
Low Offset Voltage: ±10 µV (Maximum)
Offset Voltage Drift: ±0.096 µV/°C (Maximum)
0.1-Hz to 10-Hz Noise: 3.9 µVPP
Input Bias Current: ±7 pA
Gain Bandwidth: 8 kHz
Supply Voltage: 1.7 V to 3.6 V
Rail-to-Rail Input/Output
Single in 5-pin SOT-23
EMI Hardened
The TLV8541 is an ultra-low-power op amp intended for cost-optimized sensing applications in wireless and low-power wired equipment. It minimizes power consumption in equipment such as motion detecting security systems (like microwave and PIR motion sensing) where operational battery life is critical. It also has carefully designed CMOS input stage, enabling very low, femto-ampere bias currents, thereby reducing IBIAS and IOS errors that would otherwise impact sensitive applications. Examples of these include transimpedance amplifier (TIA) configurations with megaohm feedback resistors, and high source impedance sensing applications. Additionally, built-in EMI protection reduces sensitivity to unwanted RF signals from sources such as mobile phones, WiFi, radio transmitters and tab readers.
It operates with a single supply voltage down to 1.7 V supply, providing continuous performance in low battery situations over the extended temperature range of –40°C to +125°C. The TLV8541 (single version) is available in the 5-pin SOT-23, while the TLV8542 (dual version) is available in the 8-pin SOIC package. The 4-channel TLV8544 (quad version) is available in a 14-pin TSSOP package.
For Cost-Optimized Systems
Nanopower Supply Current: 500 nA per Channel
Offset Voltage: 3.1 mV (maximum)
TcVos: 0.8 µV/°C
Gain Bandwidth: 8 kHz
Unity-Gain Stable
Low Input-Bias Current: 100 fA
Wide Supply Range: 1.7 V to 3.6 V
Rail-to-Rail Input and Output (RRIO)
Temperature Range –40°C to +125°C
Quad in 14-pin TSSOP and SOIC
Dual in 8-pin SOIC
Single in 5-pin SOT-23
Leadless Package: Dual in 8-Pin X2QFN
The OPA369 is an ultra-low-power, low-voltage operational amplifier designed especially for battery-powered applications. It operates on a supply voltage as low as 1.8V and has true rail-to-rail operation that makes it useful for a wide range of applications. The zero-crossover feature resolves the problem of input crossover distortion that becomes very prominent in low voltage (< 3V), rail-to-rail input applications. The OPA369 (single version) is offered in an SC70-5 package. The OPA2369 (dual version) comes in both MSOP-8 and SOT23-8 packages.
nanoPOWER:
OPA369: 800nA
Low Offset Voltage: 250µV
Zero-Crossover
Low Offset Drift: 0.4µV/°C
DC Precision:
CMRR: 114dB
PSRR:106dB
AOL: 134dB
Gain-Bandwidth Product: 12kHz
Supply Voltage: 1.8V to 5.5V
SC70-5, SOT23-5, MSOP-8
Low Power Sensor Signal Conditioning
*Trademark. Texas Instruments
, and TI are trademarks of Texas Instruments Inc. Other logos, product and/or company names may be trademarks of their respective owners.