[sdiy] Buffering Busses?

[Richard Wentk]

At 13:38 28/12/2005, Dave Kendall wrote:

>OK seems worth the extra money. Would just the one OPA on the 1V/OCT output
>be sufficient to feed up to 8 VCOs? I haven't yet found a really good buffer
>design, and was planning on using just a simple voltage follower. Do you
>know of a schemo anywhere, perhaps with provision for trimming any input
>offset?

If you put a voltage follower on the original output it will solve your 
buffering problems. That way you only need one rather than having one for 
every input.

You don't need super-instrumentation amps. Anything will do. It's the kind 
of thing you could use a 741 for.

Most input stages have a nominal 100k, or occasionally 10k, on the input. 
So fan out from a typical op-amp will have no problem dealing with A Big 
Number of those.

Clocks could be more of a problem because it depends on the input 
characteristics of the clock receiver - i.e. whether it's a digital or 
analogue circuit. CMOS shouldn't mind being driven by an op-amp because 
it's high-impedance anyway, although it's traditional to have a 100k 
pull-up/pull-down resistor on the input so that it doesn't float when it's 
not connected to anything.

TTL would be a problem, but I'd guess you're not using that.

Richard