On using one logic family

[mosc]

Before starting a Lunetta, it's a good idea to consider standardizing on using on logic family. We can discuss this ad nausium, but let me state a few points as general principles based only on experience.

CMOS is the logical choice because:

CMOS is very forgiving to power supply ranges. Usually, you can use virtually any DC voltage source you have.

CMOS is low-power by nature. CMOS only uses power when the logic changes from one state to another. Since our circuits will ususally clock at low frequencies (audio is very low frequency compared to usual logic rates).

TTL and others draw power constantly, so not a good choice.

The CMOS 4000 series is a good choice for standardizing because parts are cheap and readily available. 4000 logic can almost always work interchangeably with the 74C000 series, just in case. 4000 can also drive TTL in some cases as well.

So, based on the suggestion by Bugbrand himself, I think 4000 is a good logic family to start with here.

Comments welcome...

[Blue Hell]

And one CMOS output can drive many CMOS inputs (even when some conditioning input resistors are present), whereas for TTL an output drives around 10 inputs or something.

[bugbrand]

And they come in many tasty flavours too!
:::
http://en.wikipedia.org/wiki/List_of_4000_series_integrated_circuits

I've never really had the chance/need to look so much at TTL chips..

[widdly]

This page has a good information on the 4000 series...

http://www.kpsec.freeuk.com/components/cmos.htm

It doesn't cover some of the more obscure ones though.

[mosc]

TTL is really not as good for CMOS in these applications. I think 4000 series is the way to go, but if there are better choices, we're all ears.

[Uncle Krunkus]

I'm all for 4000 series.
With a 100nF across the power supply pins, 100K to ground on all inputs, and a 2N3904 buffered LED on every output, are all chances of static problems quenched?

[mosc]

No all chances of static damage, but lets try it out and see what happens.

I would prefer to tie inputs up to Vcc with a resistor, instead of ground. The reason is that if you touch the input thru a patch cable to the grounded front panel, you get a way to "play" the circuits directly "by hand". But either way is OK.

[CJ Miller]

Emitter-Coupled Logic is the wave of the future!
;]P

[mosc]

[CJ Miller]