Table of contents

RoadTest: TI SWIFT™ Power Module EVM

Author: Jan Cumps

Creation date: 3 Mar 2018

Evaluation Type: Power Supplies

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: other small footprint buck converters

What were the biggest problems encountered?: none

Detailed Review:

Verdict

The DC to DC converter performs exactly as defined in the datasheet. That's excellent.

The specs aren't the best ones around for a converter. In particular for efficiency, you find better performing ones.

That's not the point of this product. It's designed for small footprint without the need of external inductors and capacitors.

It's easy to include in your design. The PCB footprint is custom but the layout requirements are fairly standard. A double sided PCB will do.

In it's simplest configuration, a single additional standard resistor is all that's needed.

The evaluation board for the roadtest makes it straightforward to review the IC and try out its performance and configuration options.

The documentation of the EVM and the datasheet of the SWITCH IC are clear.

The https://www.element14.com/community/view-product.jspa?fsku=2707281&nsku=NULL&COM=noscriptTPSM84A21 is a valid candidate in your BOM as a Point of Load converter if the specs fit your requirements and you are looking for small footprint and a ready design.

If you can permit yourself more design time and you have more real estate available on your PCB, there may be cheaper and more efficient solutions.

Score

I've given 8 overall on functionality and documentation. An 8 is very good.

Demo Software is not applicable and I didn't need support. I've scored those 8 to not influence the total.

If there would be a score for integration value, I'd give that a 9. Clubbing a full switching circuit in a single package is very useful and allows designers to focus on the main functionality of their product.

Evaluation Module

It would be hard to get this wrong. It is in essence a single component PCB with some configuration components and plenty of probe points.

The layout is identical to the layout example in the datasheet of the switcher. For PCB designers, this is a good layout to start from.

All points in the circuit are available as probing points. For those signals where integrity is important, the PCB has breakout points that allow ground spring probes.

I'd like to have distance between signal and ground probe point a bit wider so that most common probes fit without fiddling.

There is a bank of output adjust resistors with jumpers to select the right one.

The current that can be delivered by the IC is restricted to 10 A, the maximum of the IC.

There are extra footprints for external capacitors. The user guide and datasheet document when and what is needed if you require a less noisy output or better transient performance.

Documentation is good.

SWIFT IC

This is a hybrid IC that has the switcher on board, the clock and all passive components needed for the Boost function.

Input range is 8 to 14 V, output 0.508 to 1.2 V

Little secret: without any external components, it delivers a constant 0.508 V output.

With the use of an external resistor, you can up the output up to its maximum.

The IC has protection for under voltage and over current. These are configurable.

Switching frequency is 4 MHz. You can provide your own external sync clock.

Efficiency is between 75 and say 85%, ripple without external capacitance 14 VPP (measured by me with 14 V in, 0.6 V out and 7.75 A load).

The IC has a soft start. Typical ramp-up time is 4.1 ms. A Power Good pin shows when the output has reached its value.

You can up the efficiency a little by providing a 5 V bias voltage, but it's optional. Additional capacitors on in- and output can improve signal cleanness and transient handling.

The footprint is custom, but nothing that a normally skilled layout person can't define.

The case has reached a maximum temperature of 43° C in my lab, with ambient being close to 20°.

Conclusion

The biggest strength of this product is the level of integration: a full buck converter in a single small housing.

It's made to be used at Point of Load with little additional requirements on the product that it powers.

The requirements on PCB layers and cooling are low. It 'll drop in in most designs.

Comments like "0.6 V to 1.2 V is not a useful range" do not apply. If you don't need to step down 8 - 14 V to 0.6 - 1.2 V, then this IC is not for you .

Additional Blog

There's a lot of detail in the additional posts.

I've actually checked the above claims. Here are the articles on our element14 community: