SN74LVC1G11: SN74LVC1G11 application questions

James Zhan

Part Number: SN74LVC1G11
Other Parts Discussed in Thread: SN74AHCT1G125, SN74AHC125

Hi team,

My customer want to use SN74LVC1G11 in their design and have some questions as below, could you please help to check and provide some advice?

Thanks!

If VCC=5V, input signal is 3.3V, could it be recognized as high?
If VCC=3.3V, A=5V signal, B=3.3V signal, C=4.7 signal, could it be working reliable for long time?
Customer put a 4.7kohm from 5V to VCC, and found the Vcc PIN become 4V. Why would 4.7kohm divide 1 volt?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 244220 points

1. No; V_IH is 3.5 V. To convert from 3.3 V to 5 V, add a buffer with TTL-compatible inputs (e.g., SN74AHC125, or multiple SN74AHCT1G125).

2. Yes; LVC (and AHC) inputs are overvoltage tolerant. See [FAQ] Is the reliability of a logic device affected by applying an input voltage larger than the supply (VCC)?

3. Ohm's law says that a current of 200 µA flows. Anyway, the power supply must be regulated; it is not possible to reduce the supply voltage with a single resistor.

Logic

Logic forum

SN74LVC1G11: SN74LVC1G11 application questions