SN74AVCH4T245-EP: Pull-up/Pull-down resistors

Marvin Gasis Arcangel

Hi Team,

The datasheet of CAVCH4T245MRSVREP states that “Active bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.”

I would like to know if a pull-up/pull-down resistor is allowed on the outputs of CAVCH4T245MRSVREP? What would happen if there is?

The direction input of the CAVCH4T245MRSVREP is tied High or Low in our application for each device.

Regards,

Marvin

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 256660 points

All I/O pins are inputs and have bus-hold circuitry. But as long as a pin is always used as an output, resistors are allowed. (They have an effect only when the translator is powered down.)

0 Jack Guan over 1 year ago

TI__Mastermind 19941 points

Hey Marvin,

Clemens' is correct here- if the DIR pin is always in the same state, then adding resistors on the output side is acceptable since bus-hold only effects the input (by holding it to a valid level).

Regards,

Jack

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SN74AVCH4T245-EP: Pull-up/Pull-down resistors