We are using N-Type Enhancement MOSFET to control power supply to the sensor.
- MOSFET: AO3400
- Sensor: ICM-20600
With this circuit we didn't have problems in our software. But since both gate control voltage and Vdd on the drain side are 3.3V, it caused high voltage drop on transistor.
In other words, we just moved the load to the drain side to have higher Vgs.
Now voltage drop on the transistor is very low, but we have problem in the software. Now, we have to add a delay of ~200ms after turning on the transistor, in order to use the sensor (by use I mean read I2C registers). It doesn't work otherwise. Now I want to understand what causes this delay.
Some interesting observations:
- When multimeter was connected in voltage measurement mode between ICM GND pin (drain) and GND (source), it was working great. Once disconnected issue started again.
- We added capacitor on Vdd side, it fixed problem for some time. But later issue happened again with this configuration.
Pins 5, 6, 7, 8, 11 and situationally pin 1 (address pin) have GND connections. I have suspicion that it may also cause problems. You see, earlier, since load was on source side, these ground connections were direct. Now, they go trough transistor. When all these pins(1,5,6,7,8,11) are connected to transistor drain side, issue persists.
If someone have any ideas please let me know. I need to fix this delayed behavior.