[sdiy] Re: 7400 / 4000 series ICs--compatible?

[harrybissell]

Danger Will Robinson

Some of the 4000 series will run at 3V, but not all. I would
be very careful about choosing only those devices that DO
work well. The biggest problem will be that they will have
almost no drive capability at 3V and the gate capacitance
isn't getting any smaller. I've seen some that flaked out
long before 3V

H^) harry

Scott Gravenhorst wrote:

> Phil Harbison <alvitar at comcast.net> wrote:
> >
> >I'm not familiar with that specific part, but the differences
> >between 40xx, 74HCxx, and 74HCTxx parts are primarily related
> >to supply voltage and input thresholds.
> >
> >40xx:    Vdd ranges from +5V to +15V
>
> I've seen data sheets that show min. Vdd at 3V.
>
> >74HCxx:  Vdd +5V, CMOS compatible input levels
> >74HCTxx: Vdd +5V, TTL compatible input levels
> >
>
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