Hi,
We use the TI PCA9518 for the SMBus expand function, and now, we found the SMBus waveform is abnormal, please refer to below test validation:
1. We test the PCH to PCA9518 SCL and SDL waveform, the waveform is oscillating abnormally, the waveform as below:
2. We test the PCA9518 to RAM, the SDA is abnormally:
3. We modify the design as below:
1) We push up the VPP2_5 with 3.3Kohm resistor on the circuit SDA/SCL to RAM
2) Parallel the 3pF and 10pF capactance;
There are no any improvement for the waveform;
4. We test the NXP PCA9518PW instand of TI PCA9518, the waveform is normal;
Per check the compara with TI and NXP PCA9518, thare are no more any difference between these two device except the below
So please kindly help to check how to solve this issue, thanks.
The NXP PCA9518PW for your evaluation.