SN74LVC1G32: What is correct VIH

Leo Hsieh

Prodigy 10 points

Part Number: SN74LVC1G32
Other Parts Discussed in Thread: SN74AHCT1G32

Hi TI

There are tow questions that need to confirm.

1.When Vcc is 5V, the threshold is Vcc×0.7 or VM(Vcc/2) ?

If the input voltage is 3V, can it operate normally?

2.And why the TI solution VIH is around 3.5V(5V*0.7), but other vendor is around 2V-2.2V?

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 268300 points

The actual switching threshold will be somewhere near V_CC/2. But if an input stays in the range between 0.3 × V_CC and 0.7 × V_CC, the device will not operate normally because you have violated the Δt/Δv limit; see [FAQ] How does a slow or floating input affect a CMOS device?

What other vendor has 2 V? I'd guess that that device is the equivalent of the SN74AHCT1G32, which has been designed for lower input voltages.

Logic

Logic forum

SN74LVC1G32: What is correct VIH