TPS544C20: CNTL Pull Up Resistor Value

Russell Wetherley1

Part Number: TPS544C20

Hello E2E,

My customer has found that there is a pull up resistor on the CNTL pin of the TPS544C20 via trial and error. This is causing the node to rise to a higher than expected value and causing the voltage to exceed Vmax on another TI switcher.

What is the resistance of the CNTL Pin?

Are there any issues with having 2 CNTL pins attached to the same node?

Can the internal pullup be disabled?

Thanks!

Russell

over 6 years ago

0 Mathew Jacob1 over 6 years ago

TI__Expert 5910 points

Russell,

The CNTL pin has an internal pull up of 10uA max. I don't think the internal pull can be disabled. It is possible to program the parts via PMBUS to always startup irrespective of state of CNTL pin.

Regards,
Mathew

0 Russell Wetherley1 over 6 years ago in reply to Mathew Jacob1

TI__Expert 4255 points

Matthew,

The current situation is that this leakage is causing a resistor network to see voltages exceeding the Vmax of an I/O pin on another TI switcher. Units are already in the field. If we program the part to startup irrespective of CNTL pin state, will that leakage current still be there?

Thanks!

Russell

0 Mathew Jacob1 over 6 years ago in reply to Russell Wetherley1

TI__Expert 5910 points

Russell,

Yes the pull up will still be there but at least you can de-populate the resistors feeding the CNTL pin of this IC.

Regards,
Mathew

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TPS544C20: CNTL Pull Up Resistor Value