Re: virtual ground problem

From: sleeper75se (sleeper75se_at_yahoo.se)
Date: 2002-01-25 17:07:45


Hi Joerg,

--- In buildcheapeeg_at_yahoogroups.com, "Joerg Hansmann" <info_at_jhansmann.de> wrote:
> Input HF rejection could be alternatively done with Cs to digital
> GND (or -2V). However my ESD/user protection circuit would not
> work when connected to -2V.

> Another advantage of bypassing the output of the rail splitter is
> reducing the output noise level of the rail splitter (in this case
> a TLC272 op amp).

Hmm, I guess it comes down to that then, if you want the user
protection, and lower noise, and HF immunity. If you could get rid of
that ringing...

>
> BTW: Ringing can also appear with LDOs used with wrong bypassing.
> How is this solved in TinyEEG ?

It appears that most LDO regulators are happy if ESR is low (around
0.1 - 1 ohms) and capacitance high (more than 1-10uF), so that's what
I'll use: 100uF, 0.3ohms ESR, aluminium electrolytics. Low ESR 100uF
tantalums are $7.50 a piece, :o(. I have not done any simulations yet
though.

Regards,

Andreas



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