We have a carrier board for the Jetson Orin NX / Nano series module, and have a question regarding the PMIC_BBAT current specification in the datasheet.
In the Electrical Characteristics table, the PMIC_BBAT current is listed as 12 µA (Min) to 50 µA (Max). I searched the forum and found the link below, which indicates that the 50 µA value represents the worst-case condition.
However, my customer is concerned about the 50 µA value and its impact on battery life (CR2032 battery, e.g., 200 mAh / 50 µA = 4000 hours). Could you help confirm the following:
Is my understanding correct that 50 µA is the absolute maximum under worst-case conditions (e.g., 85°C), and not the typical operating current?
Is there any official document or statement that explicitly explains this distinction, which I could share with my customer?
Is there any document that specifies the PMIC_BBAT current when the module is powered only by the RTC battery (i.e., no main power supply)?
I’ve already checked the datasheet and the “Absolute Maximum Ratings” section, but I want to make sure I’m interpreting everything correctly.
Correct, Trumany’s comment about 50uA is the maximum in worst case conditions. 50uA is not typical.
No documentation currently specifies the current with the “typical” and “maximum worst case” wording. The 12 to 50uA mentioned in section 3.5 “PMIC_BBAT” of both the Orin NX and Orin Nano datasheets gives the range. Typical is closer to the 12uA value.
The current specified in section 3.5 of the datasheets applies when the module is only powered by the backup battery and VDD_IN is off.
Thank you very much for the clarification — this is really helpful.
I would like to follow up on the test conditions for the 12–50 µA PMIC_BBAT current mentioned in the datasheet (Section 3.5).
Could you help clarify the following?
Under what specific conditions does the current vary between 12 µA and 50 µA?
For example, does it increase during active communication (such as I²C bus activity), or is it expected to remain relatively stable within that range during normal backup operation?
We also performed a measurement on the R11 resistor in power-off state (as shown in the screenshot below) and observed a current of only 0.03 µA, which seems much lower than expected.
Could this be due to our measurement method, or is there a possible misinterpretation of the test setup?
There shouldn’t be any I2C or other activity when the backup battery is used, so it should be relatively stable. There could be some variation due to ambient temperature of the module and part to part variation between modules.
1k is pretty low to be measuring single microamps, which would be single millivolts across that resistor. You could bump it to 100kohm or 1Mohm 1% tolerance just for this measurement. Ideally a picoammeter would be used in place of R11.
Thank you very much for the detailed explanation — this is really helpful.
Regarding the R11 measurement, we followed your suggestion and replaced the resistor with a 1MΩ resistor for better accuracy. However, we still observed a current of only 0.03 µA in the power-off state (as shown in the screenshot below), which remains much lower than the datasheet specification.
We’re trying to get a clearer picture of what the expected typical current should be in a real-world power-off scenario (e.g., at room temperature, no I2C activity, only RTC backup).
Could you help share:
Based on your experience or internal data, what is the typical PMIC_BBAT current we should expect under normal conditions (e.g., 25°C, stable power-off state)?
Is there any reference design or application note that provides more insight into the expected current range for the Orin NX/Nano series?
Could there be any other factor (e.g., module configuration, software state) that might cause the current to be this low?
We want to make sure our hardware design and measurement approach align with the module’s actual behavior.
With the 1Mohm resistor, the voltage drop across the resistor should be checked with the DMM and then the current can be calculated, but your photo shows the DMM directly measuring current. DMMs are usually not reliable for directly measuring current in the microamp range. So the larger resistance with 1% tolerance and DMM measuring voltage across it is a good alternative if a picoammeter is not available.
After conducting several experiments, we found that the RTC must be enabled first; only then does it begin timekeeping and reflect the correct standby current on the +VBBAT path. Measurements taken before enabling the RTC do not represent the actual RTC consumption.
After enabling RTC and removing DC power, the voltage drop across the R11 (1 kΩ) resistor is approximately 16.2 mV, which corresponds to roughly 16.2 µA of RTC current.
