SN74ABT827: sn74abt827

david sabalesky0

Intellectual 275 points

Part Number: SN74ABT827

I would like to know if having a pullup on the output of the SN74ABT827 creates any issues with the specifications.

The VCC is +5V and the pullup is 10K to VCC.

Normally Cmos outputs do not like to have pullup or down resistors.

This part does not have a high side output diode to the VCC rail. It only has a low side diode to GND.

Hence the caveat is in the specifications and it appears that adding a pullup to VCC can potentially inject current into the output pin which generally is not accepted without high side diode.

Are there issue with this pullup on the output?

over 5 years ago

0 Emrys Maier over 5 years ago

TI__Guru* 96681 points

Hi David,

The SN74ABT827 isn't a CMOS device - it is a BiCMOS device.

The outputs use this structure:

(Image from application report "ABT Enables Optimal System Design")

I don't see any problem with adding a 10kohm pull-up to the output -- especially if it's to the same supply voltage.

0 Karan Kotadia over 5 years ago

TI__Genius 16725 points

Hello,

There may be issues depending on what size pullup you use. The datasheet lists an abs max of 128mA into the output in the low state, will this condition be met?

Thanks!
-Karan

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SN74ABT827: sn74abt827