Real-Time Clock battery pin# (235 PMIC_BBAT) current consumption

[tsugumi]

Hello,

I have few questions regarding the PMIC_BBAT pin on the Nvidia Jetson Orin Nano and the circuit from the reference board.

1. My understanding is that pin is connected to a PMIC on the SoM (P/N : MP7960GRE-010F-Z). What is the estimated current draw from the PMIC_BBAT pin from our power source? What does this PMIC supply power to on the SoM other than the RTC?
2. The reference design includes a R222 and R560 that is DNP by default. When populating the R560, how was this 1k resistor selected and what is the purpose? Is this purely for current limiting?

Sincerely,
Tsugumi

[jerome27]

1. In addition, is there a specific reason why a 40V 3A schottky was specified on the schematic?

• I saw on another post that it is just to prevent reverse current in the case that the on board caps on the SOM side is charged.

[sgursal]

Please refer to Jetson Orin NX Series Modules Data Sheet

Jetson-Orin-NX-Series-Modules-Datasheet_DS-10712-001_v1.5.pdf

[sgursal]

Schottky diode is to prevent reverse current flow in to the battery. Schottky diode voltage and current rating could be much lower than what is used in the reference design. You can choose depending on your needs. Again, 1K resistor is to limit the amount of current flow.