> I asked about a LK112SM33TR LDO regulator recently (datasheet below). =A0=
To
> achieve the output ESR rating for stability I have decided to use a 10 uF
> tantalum capacitor. =A0Figure 21 of the datasheet says that the min. requ=
ired
> ESR is 0.03 ohms and the 10 uF tantalum should meet that. =A0 I will be
> placing it very close to the output of the regulator.
>
> My question now has to do with by-pass caps. =A0I've got a PIC, MCC card,
> graphic LCD, buzzer and a OEM GPS board all connected to this power supply
> and I designed the board with by-pass caps scattered around the board to
> prevent glitches on the supply lines. =A0I was going to use either 0.1 uF=
 or 1
> uF ceramic caps. =A0These have very low ESR and since everything is very
> compact on a small board I'm wondering if the close proximity of the by-p=
ass
> caps to the regulator will mean that the ESR of the tantalum cap will be
> negated and I may run into stability problems.

You should be able to achieve 0.03 ohm minimum withe some carful un-designi=
ng.
A sad solution.

The Microchip TC1224 may work for you if 100 mA max is enough.
Different pinout.
Shutdown.
ESR is specd at a MAXIMUM value.

Different pinout.
SOT23-6 with shutdown.


       http://ww1.microchip.com/downloads/en/DeviceDoc/21368b.pdf


Russell

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