BQ27520-G4: NG samples doesn't send ACK for 0x55 address

Hello Yaita,

I have not seen this behavior before, it looks like some high frequencies have coupled in with the line. Are there any high frequency traces near the communication lines?

Sincerely,

Wyatt Keller

Hi Wyatt-san,

I apologize for late reply.
I had my customer captured the waveform of VCC and REGIN, it seems VCC (Regulator output of BQ27520-G4) causes the issue because REGIN is relatively stable.
I also heard there is no such high frequency (about 65MHz) traces near the communication lines.

CH2: SCL
CH3: SDA
CH4: VCC


CH2: SCL
CH3: SDA
CH4: REGIN


I believe the NG sample is a defective part and it is better for us to send it to TI analysis.
What do you think about it?

Best Regards,
Yaita

Hello Yaita,

What is the occurrence rate of this? I am very doubtful that this is originating from the gauge, since the highest frequency on the gauge is the HFO at just above 8MHz, there's nothin on the gauge that could cause this kind of noise.

Can you share the schematic of the system so we can review?

Sincerely,

Wyatt Keller

Hi Wyatt-san,

I will request the schematic to my customer.
Could you send me a private message for share the schematics if we get it?
I would like to share it in off-line.

Best Regards,
Yaita