[sdiy] uPD444 RAM battery power

Colin f colin at colinfraser.com
Fri May 29 10:58:54 CEST 2015

> This CR-8000 I'm working on uses this CMOS static RAM. The machine has a
> battery compartment for 3 x 1.5 volts AA batteries to retain data.
> I would like to replace this with a CR2032 lithium battery or similar to
> space for mods.
> The datasheet for the RAM says data retention voltage min = 2 volts,
> 0.01 microA.
> The battery power line has diode protection from reverse voltage via the 5
> volt line.
> Any foreseen problems doing that?

I've had a CR2032 in my 303 for years, backing up 444 SRAMs with no problem
at all.
A Schottky diode is a good idea, to minimise voltage drop.

Colin f

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