RTC Power Calculation

specneeraj — Thu, 30 Jul 2026 04:54:49 GMT

Hello NXP,

We are calculating battery life for RTC for which active & sleep current are required for SNVS power domain in RT1176.

However refer to datsheet IMXRT1170BIEC - Table13, page 35, only sleep current is given.

Please let us know the factors affecting the active current and various calculations related to active current for the SNVS power domain.

Re: RTC Power Calculation

Gavin_Jia — Mon, 03 Aug 2026 07:15:33 GMT

Hi @specneeraj ,

Thanks for your interest in NXP MIMXRT series!

VDD_SNVS_IN supplies power to the SNVS/RTC domain. This domain is an always-on, low-power domain that primarily maintains the 32 kHz RTC, SNVS logic, and related wake-up and safety functions. Its current consumption is only weakly correlated with the active/sleep states of CM7/CM4; therefore, the VDD_SNVS_IN values for the SNVS mode listed in Table 13 are not omitted “sleep-only” data, but rather baseline values that can be used in RTC backup scenarios.

If the coin cell only provides power when the main power source fails → Use the SNVS mode current estimate directly;
If the coin cell also supplies power to VDD_SNVS_IN while the system is active, calculate the average current based on the active/SNVS duty cycle.

The main factors affecting the SNVS current include temperature, VDD_SNVS_IN voltage, process variations, leakage from the 32 kHz RTC crystal/board, external leakage from SNVS-related pins, and whether the device has actually entered SNVS mode. Please refer to AN13104 for more details.

Best regards,
Gavin

topic RTC Power Calculation in i.MX RT Crossover MCUs

RTC Power Calculation

Re: RTC Power Calculation