Hi guys

In digital circuit, say a gate there is a state of either LOW of HIGH, and usually a typical chip can operate from 3v to 18v, so how to I know what voltage rang is LOW and what range is HIGH?

take this one for example:
http://www.ti.com/lit/ds/symlink/cd4011b.pdf

Thanks guys

Zhuhua

 

never mind, I found it in the datasheet, I should have look harder

 

In CMOS 4000 series we treat LOW if voltage is lower then 1/3Vdd.
And we have a HIGH state if voltage is greater than 2/3Vdd.
And the threshold voltage at 1/2Vdd