I'm measuring the voltage drop off R705 (SPF-29090_C schematics) to see the power consumption off the coin-cell battery. I turn on the board with DC adapter and coin cell both plugged in and then after bootup, I disconnect the DC adapter. The measurement over the 1K resistor at R705 was 115mV which is higher than we'd like.
From AN5170 - App Note - I.MX 6Ul Power Consumption Measurement 4.4 Notes. They suggested switching boot_mode[1:0] to 2b'00 after system boot up. I did this and the measurement off of R705 is now 85mV.
It also suggested to remove U2101 and leave the Tamper Pins floating. I do both of these things and no change.
I also tried removing R761 to see if it would make any difference. The measure off of R705 is now 56mV. Is it possible to tie this pin to DCDC_3v3 instead?
The first thing on the note section is: 1. POR_B pin setting: GPBIT[1:0] set to 2b’01;
Can anyone please explain what this means? I'm hoping this is the key to saving a bit more power?
Thanks in advance,