ASM51

Alesandro F Zagui escreveu:Qual a diferença entre os CIs 74HC164 e 74LS164?

http://www.kpsec.freeuk.com/components/74series.htm

General characteristics

There are several families of logic ICs numbered from 74xx00 onwards with letters (xx) in the middle of the number to indicate the type of circuitry, eg 74LS00 and 74HC00. The original family (now obsolete) had no letters, eg 7400.

The 74LS (Low-power Schottky) family (like the original) uses TTL (Transistor-Transistor Logic) circuitry which is fast but requires more power than later families. The 74 series is often still called the 'TTL series' even though the latest ICs do not use TTL!

The 74HC family has High-speed CMOS circuitry, combining the speed of TTL with the very low power consumption of the 4000 series. They are CMOS ICs with the same pin arrangements as the older 74LS family. Note that 74HC inputs cannot be reliably driven by 74LS outputs because the voltage ranges used for logic 0 are not quite compatible, use 74HCT instead.

Alesandro F Zagui escreveu:Kodaira, agora ficou tudo mais claro. Então o LS pode trabalhar numa freqüência maior que o HC.

Fabim, muito bom esse link vou estudar mais sobre a familia 74.

Obrigado pessoal. []'s