cost effective capacitor for 3.3V regulator - what's used on the Pololu?

Hello,
I’m learning more about capacitors on 3.3V regulators, how they’re used, and the effect of ESR on efficiency and ripple current.

Can you tell what type of capacitor is on the Pololu 3.3V regulator?

And can you comment on the quality of this capacitor in hot or cold tempeatures? Or how efficient it is?

If I made my own 3.3V regulator circuit from any of the number of TI or Maxim chips, is it just the output capacitor that I have to worry about ESR and be more picky with? Can the input capacitors be the $0.01 ceramic disc or electrolytic capacitors I already have a lot of? This is for an outdoor application, so summer temperatures get up to 110F and winter gets down to -10F. Maybe put two capacitors in parallel to improve ESR?

This regulator will be used for to power the ATMEGA328 chip as well as the wireless nRF24L01 module, in a battery application. So energy efficiency is a concern. I’m on the fence about whether I should just get the Pololu or try to make my own 3.3V power circuit. The Pololu lists typical quiescent currents less than 100uA (that’s .1mA right). The Maxim 756 chips list Iq somewhere in the 60uA, but maybe if I use commonly available parts, I’m making compromises that increase Iq anyways and I might as well buy the Pololu at $6 each. The Pololu is designed by people who know what they’re doing, where as I might just be using what’s on hand.

Thanks!

Any regulator chip will have specific instructions on what to use for capacitors. Just follow the datasheet’s recommendation.

This Pololu board is using ceramic capacitors. They seem to be putting them in parallel to keep the ESR low. But, again, a low ESR isn’t necessarily a good thing – you have to follow the datasheet for your particular chip. Linear LDO regulators (e.g. LM1117) become unstable if the ESR is too low, for example.

Chagrin: This Pololu board is using ceramic capacitors. They seem to be putting them in parallel to keep the ESR low.

Actually its more likely to keep the price down, large MLCC's get very expensive as they are not high-volume items.

Ceramics are usually the best type for this. If in doubt, use ceramic.

Second choice would be polyester.

Do NOT use electrolytic or tantalum.

Atmel wrote a paper on it, let's see....here it is: http://www.atmel.com/Images/doc0484.pdf

However, there is a big difference between decoupling caps near an IC (Which are mid to low capacitance) and anti-ripple caps that you can use on the outputs of a regulator, which are usually high capacitance. The biggest deciding factor is what your regulator says you need, followed by how much current will you need to instantaneously source (Which is unlikely to be necessary).

mirith: However, there is a big difference between decoupling caps near an IC (Which are mid to low capacitance) and anti-ripple caps that you can use on the outputs of a regulator, which are usually high capacitance.

Try this doc instead: http://www.ti.com/lit/an/slta055/slta055.pdf