what CMOS/TTL output mean?

[chang830]

Hi,
I know, the CMOS/TTL input means the device works OK when input CMOS level or TTL level. But what the CMOS/TTL output mean? It mean the device can output either the CMOS level or TTL level? Or it mean it output CMOS level(if the device is CMOS circuit), it can also drive the TTL input of the following device?

Thanks in advance for the help!

 

[IanP]

"Interfacing to MM74HC High-Speed CMOS Logic"
https://www.fairchildsemi.com/an/AN/AN-314.pdf

Regards,
IanP

 

[dachou]

ya
ttl means transistor-transistor logic.
this kind of logic talking about currnt or you can say bjt.
cmos is voltage controlled device.
so, while you design cmos output with ttl comparable, you need set driving current to specific spec while output voltage in voh and vol.

 

[vbhupendra]

TTL o/p means Voltage levels compatible to TTL logic (0.8 for VIL, 2.4 VIH) (0.4 for VOL, 2.8 for VOH)
& CMOS o/p (0.3VDD for VIL & VOL, 0.7VDD for VOH & VIH)