[volt-nuts] Micrel Ripple Blocker

[David]

On 12 May 2013 23:51:38 -0400, kevin-usenet at horizon.com wrote:

>> The Micrel datasheet shows a pretty standard source follower
>> configuration.  I checked similar low dropout/low noise regulators
>> from Linear Technology and they have similar output noise and power
>> supply rejection.
>
>A source follower is an unusual choice for an LDO, since in theabsence
>of a separate bias supply input, it requires a complex charge pump to
>bias the gate.
>
>re there a significant number like that?  The LTC3035 uses that style
>internally, but is optimized for VLDO, and only has 40 dB attentuation at
>100 kHz, rather than 60.
>
>Could I inquire which parts you looked at that had similar PSRR?
>They would be useful to know about.
>
>Thank you!

The Micrel data sheet shows an internal charge pump to create the bias
supply.

I am not sure now which Linear Technology parts I looked at.  I did
assume an external bias supply instead of a common emitter/source
topology.