PCA9534: PCA9534PWR-SDA random low

Shenhua,

How repeatable is the issue?

How was the customer able to confirm the PCA9534 was the cause? (did they remove all I2C devices on the bus except ours? Did they do an ammeter check?)

What does the Vcc power up ramp rate look like?

-Bobby

Bobby

I am the hardware engineer of CIG, and I raised this PCA9534 issue.

The issue is repeatable，Signal of SDA could be found low almost every time when the board power on if the failed PCA9534 is on board.

We found this failed PCA9534 by Cross-validation. Signal of SDA keeps low when we remove all other I2C devices on the bus, but it will return to normal if we remove PCA9534. We checked these signals by Oscilloscope.

Below pictures are the Vcc Power up waveform  and power down waveform. There is no abnormal conditions showed on the Vcc power up ramp rate.

Bobby

I am the hardware engineer of CIG, and I raised this PCA9534 issue.

The issue is repeatable，Signal of SDA could be found low almost every time when the board power on if the failed PCA9534 is on board.

We found this failed PCA9534 by Cross-validation. Signal of SDA keeps low when we remove all other I2C devices on the bus, but it will return to normal if we remove PCA9534. We checked these signals by Oscilloscope.

Below pictures are the Vcc Power up waveform  and power down waveform. There is no abnormal conditions showed on the Vcc power up ramp rate.

BOBBY said:

ramp rate

BOBBY said:

ramp rate

Since this conversation has moved offline, I will close this thread internally.

-Bobby