SN74LVC162244A: 26 ohms series resistors in IBIS model?

Michael T Schneider

Part Number: SN74LVC162244A

The SN74LVC162244A datasheet states that ‘Output ports have equivalent 26 ohms series resistors, so no external resistors are required’. I’m using the sn74lvc162244a.ibs IBIS model (rev 1.1 - dated 12-17-2004) and getting 600mV undershoot with no series, passes when adding a 33 ohm series by the driver.

Do the sn74lvc162244a.ibs output models include the 26 ohm series?

over 4 years ago

0 Chad Crosby over 4 years ago

TI__Expert 6680 points

Hi Michael,

Could you attach a picture of the schematic, and any waveforms associated with it?

Thanks!

Chad Crosby

0 Michael T Schneider over 4 years ago in reply to Chad Crosby

TI__Expert 3780 points

See below waveform in Slow and Fast corner. The SN74LVC162244A output drive directly to 1.8V cmos input. We use IBIS to check waveforms and verify overshoot/undershoot/ringbacks.

Are you saying the output equivalent series is not included and we need to add virtually a 26 ohm at the pin output?

Driver [Model] LVC162244A_OUT_18

0 Chad Crosby over 4 years ago in reply to Michael T Schneider

TI__Expert 6680 points

Hi Michael,

The series resistor mentioned in the datasheet is included in the IBIS model.

If you have any other questions, please don't hesitate to reach out.

Thanks!

Chad Crosby

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SN74LVC162244A: 26 ohms series resistors in IBIS model?