bogdanfirst said:
does any1 know a website or has some time to tell me the differnces between the logic families HC, HCT, LS, S and other types CMOS ligic ICs?
thanks in advance
I think S is for Schottky and LS is low power Schottky, and both are TTL ICs.
Regarding the others, they are CMOS. The following is extracted from an old Mullard (since absorbed by Philips) handbook:
"The HCMOS family of ICs is manufactured using a 3um silicon-gate CMOS process. HCMOS ICs have the low power consumption, high noise immunity, and wide temperature range of earlier CMOS ICs. They also have the high speed and drive capability of bipolar low-power Schottky TTL (LSTTL). They are immune to latch-up.
"Many HCMOS are pin-compatible with existing 54/74 LSTTL and HCMOSB logic ICs. HCT types are ideal replacements for LSTTL types. HCT can also interface between TTL and CMOS ICs.
"Three types of HCMOS are available:
- 74HC: CMOS input switching levels 30% and 70% of Vcc (typically 50%). Supply voltage 2V to 6V.
- 74HCT: TTL input switching levels 0.8V and 2V (typical switching threshold 28%Vcc). Supply voltage 4.5V to 5.5V
- 74HCU: CMOS input switching levels 20% and 80% (typical switching threshold 50%Vcc). Supply voltage 2V to 6V. Unbuffered outputs to allow operation in the linear mode.
ADDITIONAL FEATURES:
* DC noise margin of 74HC types is 3 times that of TTL.
* Logic output levels are 0.1V and Vcc-0.1V
* Typical gate progagation 8ns.
* Can operate up to 60MHZ
* All types, except HCU, are fully buffered.
* Fan-out capabilty = 10 LSTTL loads (4mA). Bus-driver types fan-out is 15 LSTTL loads (6mA).
* Analogue switching types can operate up to 10V.
* Symmetrical output source and sink currents.
* Equal output rise and fall times.
* Inputs protected against electrostatic discharge."
I hope that helps.