i.MXRT1060 Power sequences and connections.

[gpira]

Hi everyone,

I'm designing an application using a i.MXRT1062 and I have some doubts about the power system.

I have an external DC-DC that provides 3.3V to the micro.

I have connected it to VDD_HIGH_IN, VDDA_ADC_3P3 and DCDC_IN.

VDD_SNVS_IN is connected to another source cause I need the RTC always on to keep up with the date and hour.

Is it mandatory to utilize PMIC_ON_REQ to enable the DC_DC? What does it happens if I don't? Can i leave it unconnected? And what about PMIC_STBY_REQ?

I'm not planning on use the ONOFF and WAKEUP pins, can i leave them floating?

Thanks in advance 

BR,

Giacomo

[mjbcswitzerland]

Hi

The main source of info is the 1050 design guide.

See also the Teensy 4 design for a fairly minimum circuit: https://www.pjrc.com/store/teensy40.html#power
If you search on the site there is a good interactive diagram that explains the power sequencing as they have implemented it.

See also the following for an intelligent power sequencing method with other space saving features and power cycling watchdog: https://www.utasker.com/docs/iMX/uTasker_iMX_WDOG.pdf
That is what I use for 1062 designs (for which I have a minimum reference design) since it gives full control and maximum reliability at minimum component count/cost (as well as optional very low power RTC with programmable power down periods commanded by the 1062 itself).

Regards

Mark

P.S. For 1062 stock see https://www.utasker.com/Shop/semi.html

[RaRo]

Hello @gpira,

First of all, we like to apologize for the delay to answer you.

Is it mandatory to utilize PMIC_ON_REQ to enable the DC_DC? What does it happens if I don't? Can i leave it unconnected? And what about PMIC_STBY_REQ?

It will depend in your application. PMIC_ON_REQ is used to assert and enable an external DCDC to power up all other power domain, as mentioned in the Hardware Development Guide for the MIMXRT1050/MIMXRT1060 Processor, but if you are not going to use them you could leave them unconnected.

I'm not planning on use the ONOFF and WAKEUP pins, can i leave them floating?

Yes, you could leave them unconnected if they are not being used.

Best regards, Raul.