[sdiy] A20G545 chip, what is it?

Mike Bryant mbryant at futurehorizons.com
Sun Jun 19 16:14:31 CEST 2022

Possibly an LM389 transistor array equivalent

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of John Speth via Synth-diy
Sent: 19 June 2022 14:58
Subject: Re: [sdiy] A20G545 chip, what is it?

Photo at: https://myplace.frontier.com/~jspeth/A20G545.JPG

I should have posted this pic first. The date code accurately indicates when I built it: 1983. So anything with origins past that date are not valid.

Thanks - JJS

On Sunday, June 19, 2022, 06:05:02 AM PDT, <synth1 at airmail.net<mailto:synth1 at airmail.net>> wrote:

I'm pretty good at this if I can SEE a photo.

Paul S.

-----Original Message-----
From: Synth-diy <synth-diy-bounces at synth-diy.org<mailto:synth-diy-bounces at synth-diy.org>> On Behalf Of brianw
Sent: Sunday, June 19, 2022 3:16 AM
To: John Speth <johnspeth at yahoo.com<mailto:johnspeth at yahoo.com>>
Cc: SDIY <synth-diy at synth-diy.org<mailto:synth-diy at synth-diy.org>>
Subject: Re: [sdiy] A20G545 chip, what is it?

My first guess was a 74x545 octal bidirectional transceiver, non-inverting.
They're 20-pin.

However, that doesn't seem to fit on a SSM voice card (or into an 18-pin


On Jun 18, 2022, at 7:59 PM, John Speth wrote:
> Today I was dumping old circuit boards that I built many years ago. I was
stripping valuable parts from one and I found two 18 pin DIPs that are
marked "A20G545" on one line and "MCE 8211" on the line below it. 8211 is
the date code (1982). The other markings are a mystery. Searching for this
chip online was a dead end for me. Does anybody know what it could be? It
was from a board that contained an SSM 2012 VCA and an SSM 2044 VCF. I've
lost the schematics. It was my design.
> Thanks - JJS

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