Regarding SNVS outputs of of i.MX RT1170 controller MIMXRT1176CVM8A

[Deepak_India]

Hi Team,

We are using MIMXRT1176CVM8A in our project. We are using internal power management for the controller.

We have tied DCDC_IN, VDD_LPSR_IN and VDD_SNVS_IN to Vdd_3V3 volts.
The SNVS LDO output i.e VDD_SNVS_ANA is tied to NVCC_SNVS. Please refer the below image.

Since we have tied VDD_SNVS_ANA to NVCC_SNVS and that NVCC_SNVS needs voltage less than 1.95V, We are facing an issue. We are getting 2.21 Volts at VDD_SNVS_ANA and 0V at VDD_SNVS_DIG.

Please revert us what could be the problem wrt SNVS connections since we followed the recommendations as per Evaluation board Schematics of MIMXRT1176CVM8A.

[Gavin_Jia]

Hi @Deepak_India ,

Thanks for your interest in NXP MIMXRT series!

i.MX RT1170 Crossover Processors Data Sheet for Industrial Products mentions that the power rail VDD_SNVS_DIG is controlled by software:

[IMXRT1170IEC. Section 4.2.1.1. Power-up sequence]

You could turn on and off the power rail by software with function PMU_SnvsDigLdoInit and PMU_SnvsDigLdoDeinit of driver fsl_pmu.c in the MIMXRT1176 SDK.

Best regards,
Gavin

[Deepak_India]

Hi @Gavin_Jia 

Your response regarding VDD_SNVS_DIG is fine. 

Can you please let us know about the condition of VDD_SNVS_ANA. What is the reason for 2.21V at VDD_SNVS_ANA?

Regards

Deepak 

[Gavin_Jia]

Hi @Deepak_India ,

Thanks for your kind patience. This issue is indeed rare, so I confirmed it with experts internally.

From the response given by the expert, I got that first of all, reviewing your schematic does not reveal any problem. Then, Although VDD_SNVS_ANA is slightly higher than the guide calls for, it should be a non-issue (if nothing else). You can try running a simple demo in the SDK to test it. Finally, regarding the cause of the high measured voltage at this point, we recommend that you have the PCB inspected to rule out leakage elsewhere.

Best regards,
Gavin