Questions on RT1064 EVK supervisory circuit

[morphee909]

Hi !

I'm trying to understand the supervisory circuit of the RT1064 EVK to design my own board.

Here are my questions :

1 : Is it necessary to supply UM805RE from a specific SNVS LDO (VLDO_3V3 pin) ? Why not use DCDC_3V3 ?

2 : I don't understand the schottky diode circuit on UM805RE. How the MR pin goes from high to low ?

3 : Why the 10k resistor on the DCDC enable pin ? Is it a pull-up for the reset pin of UM805RE ? Datasheet asks for a pull-up on RESET. But why it is connected on PMIC_ON_REQ ?

4 : Why the 1.5k resistor on UM803RS ?

5 : UM803RS datasheet asks for pull-up between VCC and RESET but I don't find it in the schematic. Is it because the hardware design guide says “POR_B signal has internal 100K pull up to SNVS domain” ?

If someone has an answer to one of these questions I would already be great.

[_Leo_]

Hi,

Thank you so much for your interest in our products and for using our community.

I recommend you base your design entirely on the Hardware Development Guide. Since the MIMXRT1064-EVK is for evaluation purposes, the latter is only recommended for reference.

Hope it helps you.

Have a nice day!