Re: decoupling caps placement



tempus fugit wrote:

Hey all;

I've got a circuit that uses 3 4049 inverters. On this IC, the V+ is on pin
8 and the ground is on pin 1. I know that the decoupling caps need to be as
close to the IC as possible, but how can I connect 1 end of the cap to V+
and the other to ground when the pins are so far away?

With a 4049 and its slow speed it really doesn't matter. You mean a CD4049 ?

I saw one guy build a complete CMOS processor board using 4000 series and god
knows what micro, probably running at ~ 1 MHz and it had about 3 decoupling
caps spread around. Now that DID have problems but the fucking clown who sold
it claimed that CMOS "didn't need decoupling" ! Jesus Wept. We liked the
product and offered to relayout the board for free so he could supply a
reliable model but he turned us down !

The company folded of course. Both supplier and customer.

Graham

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