TMP75B: jitter issue.

Tommy Tzeng

Part Number: TMP75B

Hi Sir,

customer use TMP75BIDGKR. Could you do me a favor to answer our question of this part?

customer measured the timing of I2C interface and found that its falling edge has a jitter.any risk?
look forward your reply.

over 4 years ago

0 David Vaseliou over 4 years ago

TI__Expert 6820 points

Hi Tommy,

Yes, this is a concern since the ringing on the I2C lines could crosses the VIH and VIL levels and could cause miscommunication. This could be caused by noise, parasitics, or reflections on the I2C lines.

Thanks,

David

0 Howard Chen over 4 years ago in reply to David Vaseliou

Prodigy 60 points

Hi David,

Is there any method to solve this issue? But I don't find waveform doesn't cross ViH, ViL. Is it harmful?

Thanks.

Howard

0 David Vaseliou over 4 years ago in reply to Howard Chen

TI__Expert 6820 points

Hi Howard,

There is still risk since the change of voltage is oscillating between the two levels. To debug this you would need to check your design for electrical noise and parasitics. If your traces are long this could also be caused by reflections on the I2C signals. In which case appropriate impedance matching would need to considered and a terminating resistor may need to be added.

Thanks,

David

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TMP75B: jitter issue.