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

Phil Harbison alvitar at comcast.net
Sat Aug 27 21:51:19 CEST 2005


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
74HCxx:  Vdd +5V, CMOS compatible input levels
74HCTxx: Vdd +5V, TTL compatible input levels




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