topic Re: RT1176 Problem connecting some power rail in i.MX Processors

RT1176 Problem connecting some power rail

Tariq_Al — Thu, 30 Jan 2025 10:47:39 GMT

Hello Everyon,

I am developing a custom board based on MIMXRT1176CVM8A, and unfortunately, I could not bring the board alive via UART or JTAG.

During my troubleshooting, I found that I had mistakenly connected the +VDD_LPSR_DIG with +VDD_SNVS_DIG.

My question is, could this be a problem preventing the device from booting?

To be noted, I have done the power-on sequence correctly, but regarding the internal DC-DC, I couldn't get a 1.0V for the IN_SOC. I don't know if this problem is also related to my mistake, so I have connected an external power supply for the core voltage.

Thanks a lot..

Re: RT1176 Problem connecting some power rail

diego_charles — Thu, 30 Jan 2025 17:13:00 GMT

Hi @Tariq_Al

Thank you for reaching out!

Both VDD_LPSR_DIG and VDD_SNVS_DIG are LDO outputs that ramp-up independiently and each one have a different typical voltage (1v and 0.85v respectively ). I can not tell if this shortcircuit is the origin of your issue, but after separating them do you see any diferrence? Please do that and use the recommended capacitors on these pins as seen on our EVK.

Diego

Re: RT1176 Problem connecting some power rail

Tariq_Al — Thu, 30 Jan 2025 17:31:26 GMT

Thank you for your replay.

Actually, I have connected using polygon in internal layers, I could though saperate them by cutting the trace, but I can not put the output capacitors, would it be a problem?

Re: RT1176 Problem connecting some power rail

diego_charles — Fri, 07 Feb 2025 00:03:06 GMT

Hi @Tariq_Al

My apologies for the delayed response. Adding those caps is our recommendation to ensure that the design is robust. So I can not tell rigth away if not having them could be discarted.

Let me know if you found out anything else during the troubleshooting.

Diego

Re: RT1176 Problem connecting some power rail

Tariq_Al — Mon, 03 Mar 2025 09:06:06 GMT

Hi,

I disconnect the two power rails, and now I got these voltages:

VDD_SNVS_ANA = 1.79V

VDD_SNVS_DIG = 0.03V

VDD_LPSR_ANA = 1.8V

VDD_LPSR_DIG = 1.01V

DCDC_DIG = 0.64V !

VDDA_1P0 = 0V !

I am not sure why my DCDC_DIG output is still 0.6V and the VDDA_1P0 is 0v !!

Note: I Disconnected them on another board because I was afraid the board got damaged, so the above results are from the new board.

Re: RT1176 Problem connecting some power rail

diego_charles — Tue, 25 Mar 2025 21:57:52 GMT

Hi @Tariq_Al

I am sorry for the delayed response, Have you found something else in the meantime?

By looking at the values you measured, have seen the below issues.

VDD_SNVS_DIG = 0.03V : I see that this LDO output is still not generating power. This LDO depends on the VDD_SNVS_IN.

I am concerned about this LDO output being 0v as well. How does the power-up supply ramp looks?

DCDC_DIG = 0.64V ! : The digital output of the DCDC is not generating the expected power, but the analog does ? What is the voltage of DCDC_ANA?

VDDA_1P0 = 0 v: This LDO output gets power from DCDC_ANA. if DCDC_ANA is not generating the expected power this failure could made sense.

How does your DCDC external circuitry looks?

Thank you very much for your patience.

Diego

Re: RT1176 Problem connecting some power rail

Tariq_Al — Thu, 17 Apr 2025 08:10:02 GMT

Thank you @diego_charles.

Sorry for the late response.

I did not design any external DC-DC IC converter to supply the 1V0.

However, I supplied the 1V0 through the external power supply, and it worked! The board is functional correctly, booting, and communicating serially.

I appreciate your support.

Re: RT1176 Problem connecting some power rail

diego_charles — Mon, 21 Apr 2025 16:57:15 GMT

Hi @Tariq_Al

I am very glad to know that your custom design is now working! I wish you good luck in the upcoming stages of development.

Diego