SN74LVC125A: Waveform of VCC

na na78

Guru 16770 points

Part Number: SN74LVC125A

We obtained the following waveform of VCC (14pin) when powered up.

When powered up, OE is pulled down to GND.

Should we avoid this state of VCC for normal operation?

Should the OE be tied to VCC when powered up/down?

BestRegards

0 Clemens Ladisch over 7 years ago

Guru 244350 points

The datasheet recommends to tie O̅E̅ to V_CC during startup. This is to avoid glitches at the output.

If you do not care, you can leave O̅E̅ enabled during startup.

0 na na78 over 7 years ago in reply to Clemens Ladisch

Guru 16770 points

Thank you for your reply.

>If you do not care, you can leave O̅E̅ enabled during startup.

Yes. Now ~OE is tied to GND, so I believe the ~OE is enabled.

I'm concerned this VCC waveform has strange step part when it is rising.

So I want to confirm if such a waveform is likely to happen and it is normal.

BestRegards

0 Clemens Ladisch over 7 years ago in reply to na na78

Guru 244350 points

Do you have any bulk and high-frequency bypass capacitors?

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