BQ32000 IRQ calibration signal output stability

Daisuke Maeda said:

The IRQ pin functions as a frequency test output for the calibration.

What is the typical frequency accuracy for the calibration signal? Is it at the same level as typical accuracy of Real-Time Clock?

>>> I am not familiar with this device, so I am using the datasheet as a guide. It appears as though the calibration signal is the same level of accuracy as the Real Time Clock.

Our customer want to use the calibration signal as a clock source for external timer device.

Once the IRQ pin is configured as a frequency test output, is the signal always output without stopping?

>>> If using the 512Hz, the datasheet states that this will continue being output without stopping assuming no disruption of Vcc. If using the 1Hz with calibration, the FTF signal will be reset to zero upon cycling power on Vcc. The FTF bit would then have to be set back to 1 on each power up.

>>> In addition, the datasheet (page 5) states that when operating on backup, IRQ is unused. From this it appears the output will not continue to be output when Vcc power is not present.

Hi Daisuke,

Unfortunately, we don't have a setup to measure the duty cycle. And, the datasheet does not specify this, so it may take some time to get your answer.

The easiest method is to measure it on your system if you have a scope.

The RC time constant of the rising edge should have little impact on the duty cycle at 1Hz.

If you do measure it, would you mind posting a scope shot so everyone can benefit?

Thank you.