Re: [EE] looking for negative 5V regulator or circuit

In a battery application you might prefer a switchmode regulator?

Regards,
Mark
markrages@gmail

On Tue, Jun 10, 2025, 1:44 PM Dwayne Reid <[email protected]> wrote:

> Good day to all.
>
> I'm working on a project where I need a negative 5 Vdc rail relative to the
> incoming +12 Vdc rail.  My first thought was a bog-standard 7905B regulator
> (the "B" suffix denotes -40C operation) but this is a battery-powered
> system and the worst case bias current of 8mA is way too high.
>
> I spent some time looking at Digikey offerings but they all seem stupid
> expensive.  Can anyone suggest a part that is reasonably inexpensive and
> works down to -40C?  Current is fairly low - should be less than 20 mA
> worst case.  I sort of prefer a package larger than SOT-23 just because of
> the fairly minimal heat dissipated.
>
> My alternative is a 6.2V Zener diode feeding a PNP Darlington pass
> transistor.
>
> Suggestions and opinions greatly appreciated!
>
> dwayne
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