RTC Current optimization

[Afeefah]

Hi NXP Team,

We are using RTC PCF85263A in our device with iMX6ULL as a processor. We did explore from the datasheet that in DPDM the current consumption is less by RTC when the main supply is cutoff and the power is by VBAT supply. During this mode the RTC only saves the time, date and provides interrupts, other functions are disabled.

Can this mechanism be done in normal sleep mode so that RTC consumes the same amount of current as observed when only VBAT supply is present, even when the main supply is connected.

Kindly let us know your inputs on this!

Thanks & Regards,

Afeefah Fathima

[Sanket_Parekh]

Hello @Afeefah,

I hope you are doing well.

->Please refer to the below link.
https://community.nxp.com/t5/i-MX-Processors/imx6-RTC-Current-consumption/m-p/652982

It may help!

Thanks & Regards,
Sanket Parekh

[Afeefah]

Hello @Sanket_Parekh 

We are using RTC PCF85263A as an extenal RTC with iMX6ULL as a host processor.

Thanks & Regards,

Afeefah Fathima

[Sanket_Parekh]

Hello @Afeefah,

I hope you are doing well.

It is always recommended to use an external RTC because it often consumes more than 10 times less current than an internal RTC allowing a much smaller backup battery to be used. On the other hand, the use of an internal RTC may simplify the carrier board design and may allow wake-up using the alarm capabilities.

Please refer to the RTC Measurements in the below link.
https://developer-archives.toradex.com/knowledge-base/rtc

Please refer to section 7.8 Offset register, and 7.10 Oscillator register, from the below link, It will help you get an idea about RTC possibilities of low current consumption.
https://www.nxp.com/docs/en/data-sheet/PCF85263A.pdf

I hope it helps!

Thanks & Regards,
Sanket Parekh