INA241A: Current Sensing for very low power devices

Hello Sameer, 

Thank you for your post. 

Do you know the frequency of the noise? Can you provide a scope capture of the noise so I can size the cap appropriately? 

You can implement a targeting cap for a specific frequency. 

Best Regards, 

Joe

The INA241 has high bandwidth and passes high-frequency noise. An output capacitor can reduce visible output noise. Large capacitors also attenuate fast current transients.
Use an RC filter instead of only a capacitor. Try 100 ohm and 10 nF initially. Increase capacitance gradually if necessary. Check Bluetooth bursts remain accurately reproduced. If you are using a PCB, keep input traces short and matched. Place supply bypass capacitors near the amplifier. Your wide current range complicates shunt selection. Large shunts increase voltage drop during peaks. Small shunts reduce low-current measurement resolution. Consider lower-bandwidth amplifiers for power profiling applications. You can also use a voltage follower if your oscilloscope input, long cable, or other circuitry is loading the INA241 output.

The following write-ups may be helpful for you?

Analog Engineer's Circuit Cookbook: Amplifiers - TI E2E

INA241B datasheet and application notes

What is voltage follower

Sameer,

Thanks for your patience. Joe is out of the office today but will reply when he returns tomorrow, 7/21.

Hi Joe,

I will get back to you with the scope capture.

Thank you Rebecca for the suggestion and the write-ups, I will go through them and try to implement accordingly.