BQ76940: Clarification on I2C Clock Frequency for BQ76940 and BQ78350-R1

Arati Lal

Part Number: BQ76940
Other Parts Discussed in Thread: BQ78350-R1

Tool/software:

Dear TI Expert,

We are currently using the BQ76940 AFE in combination with the BQ78350-R1 companion IC. As per the BQ76940 datasheet, the I²C clock frequency is expected to operate at 100 kHz. However, during practical measurements, we are observing a frequency closer to 36 kHz.

Could you please clarify:

If there is a recommended method or setup for accurately measuring the I²C clock frequency?
Whether this variation in frequency is expected under certain operating conditions or configurations?

5 months ago

0 Alan Frias 5 months ago

TI__Mastermind 26395 points

Hello Arati,

This question has been assigned and will be answered when possible.

Thank you,
Alan

0 Alexis_H 5 months ago in reply to Alan Frias

TI__Genius 17835 points

Hello Arati,

Arati Lal said:
If there is a recommended method or setup for accurately measuring the I²C clock frequency?

Waveforms and/or logic analyzers can help with debugging communication line issues. This article may also be useful to refer too: How to debug I2C through waveform analysis.

Arati Lal said:
Whether this variation in frequency is expected under certain operating conditions or configurations?

The BQ76940 will never control the I2C clock, only the host. If you have any further communication questions regarding our part, Section 6 Communications of this FAQ may be usesful to refer too.

Best Regards,
Alexis

Power management

Power management forum

BQ76940: Clarification on I2C Clock Frequency for BQ76940 and BQ78350-R1