TXB0304 output ringing

Luke Sun

Other Parts Discussed in Thread: TXB0304

Hi team,

My customer now is using TXB0304 as 3wire-SPI bus level-translator. Since the PCB length is very long, ~3inch, they saw big ringing.

When the output is connected with a 20kOhm pull-up resistor, the output will be as below.

Then they moved away the pull-up resistor and put a 10pF capacitor to the output. The signal becomes worse.

Do you have any recommendation what to do on the output circuit to optimized the ringing?

Thank you!

over 9 years ago

0 Nirav Patel over 9 years ago

TI__Expert 6335 points

Luke,

Could this because of the inductance of the oscilloscope probe? I have seen overshoot of this nature when the oscilloscope probe has a highly inductive connection to GND. How are they connecting the oscilloscope probe to GND?

Best Regards,
Nirav

0 Luke Sun over 9 years ago in reply to Nirav Patel

TI__Intellectual 1830 points

Hi Nirav,

This ringing is due to the long PCB trace. And the more important is like in the second figure, the low status of the signal is very bad. Do you have any idea on that behavior?

Logic

Logic forum

TXB0304 output ringing