BQ32000: BQ32000 using questions

Kevin Chuang

Part Number: BQ32000

Hi TI FAE,

I have some questions about using BQ32000.

1. According spec, the Vback voltage(Backup supply voltage) < 1.4V, it can't run RTC. But our testing, the Vback voltage < 1.4V, it can keep running RTC until 0.8V. Is it correct?

2. Can I use Pin IRQ which generate 512Hz &１Hz to adjust RTC frequency?

3. My crystal choose EPSON FC135 (https://www.digikey.tw/product-detail/zh/epson/FC-135-32-7680KA-A5/SER4103DKR-ND/6188449), no add crystal. Is it OK?

4. After using a few hours, my find RTC time has some second deviation, is it correct?

over 2 years ago

0 Amin Eshraghi over 2 years ago

TI__Expert 6140 points

Hello,

Vback has to be greater than 1.4V per specification and that is what's recommended. Anything below that may not provide full operation and is not guaranteed.

The IRQ pin if general purpose output or frequency test output, not sure I understand how you would use it to adjust the RTC frequency?

Crystal seems okay best I can tell (a lot of the information on the DigiKey website is not in English)

It has seconds of error? Was it stopped at any point?

Regards,

Amin

0 Kevin Chuang over 2 years ago in reply to Amin Eshraghi

Prodigy 155 points

Hi Amin,

IRQ pin can generate 512Hz or 1 Hz via setting register. What is the meaning of this waveform?

English Digikey→Crystal (https://www.digikey.tw/product-detail/en/epson/FC-135-32-7680KA-A5/SER4103DKR-ND/6188449?cur=TWD&lang=en)

Not seconds of error.

Compare with correct time, it has some deviation, example 1~5 seconds.

Thanks!

Kevin Chuang

0 Amin Eshraghi over 2 years ago in reply to Kevin Chuang

TI__Expert 6140 points

Hi Kevin,

IRQ is used to correct for the crystal frequency error. This E2E post:

https://e2e.ti.com/support/clock-and-timing/f/clock-timing-forum/703635/bq32002-bq32002-improper-time#pi320966=1

Has in depth description and examples of how to use the IRQ pin. Please review the first response post on there and I believe that will clear things up.

Thanks and regards,

Amin

Clock & timing

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BQ32000: BQ32000 using questions