BQ32002: Calibrate to 32.768 kHz

Sarah Cratem

Part Number: BQ32002

Hi team!

I am looking into a solution to make a real-time clock on a design I am working on really accurate. I am working on a sound level meter that needs to have accurate timing in order to report accurate numbers to our users. We want the BQ32002 to calibrate the 32.768 kHz crystal when it starts to deviate a little bit. Can it work this way?

Thanks,

Sarah

over 2 years ago

+1 Amin Eshraghi over 2 years ago

TI__Expert 6140 points

Hi Sarah,

The calibration method on BQ32002 is somewhat manual so not sure if it would be suitable for your application or not. The process is to bring out 1 Hz output on the IRQ pin and the measure the frequency error and then adjust accordingly. Specific details are explained here in the 2nd post in the thread by Alan O: https://e2e.ti.com/support/clock-timing-group/clock-and-timing/f/clock-timing-forum/703635/bq32002-bq32002-improper-time#pi320966=1

Long term the drift would be dependent on the crystal used.

Regards,

Amin

0 Sarah Cratem over 2 years ago in reply to Amin Eshraghi

TI__Intellectual 795 points

Hi Amin,

Thank you for that post!

This would work for our application if we got a frequency counter mentioned in the post. Do you have a recommendation for a frequency counter we can use?

Thanks,
Sarah

+1 Amin Eshraghi over 2 years ago in reply to Sarah Cratem

TI__Expert 6140 points

Hi Sarah,

I don't have any specific model, really all that's required is if it's accurate enough. If mHz resolution is provided that should be sufficient.

Regards,

Amin

Clock & timing

Clock & timing forum

BQ32002: Calibrate to 32.768 kHz