SN7407 pull-up resistor

Mark Liang

Intellectual 740 points

Other Parts Discussed in Thread: SN7407

Hi,

I am using the output of a SN7407 to drive a TTL input. Do I need a pull-up resistor for the the output?

Thanks.

over 9 years ago

0 Emrys Maier over 9 years ago

TI__Guru* 96712 points

Yes - the output of this part is open-collector so it cannot drive high without an external pull-up.

0 Mark Liang over 9 years ago in reply to Emrys Maier

Intellectual 740 points

What is the recommended value for the pull-up?

0 Emrys Maier over 9 years ago in reply to Mark Liang

TI__Guru* 96712 points

The output can sink 30 mA, so as long as the pull-up does not draw more current than that with your Vcc, it will be fine. I would recommend using a 10k unless speed is an issue.

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SN7407 pull-up resistor