Edit:
After further work, we have found the issue. It was a problem with our pin configuration on the cc1312 side. By not pulling down the cs pin (and floating it with no-pull resistors) we go the power consumption down to 5uA!
Hi,
We are currently developing an IoT device that is highly sensitive to input power consumption. Our setup includes a TI CC1312R MCU paired with the BMA400 accelerometer. The BMA400's interrupt pins wake up the MCU when its FIFO buffer is full, and communication is handled via SPI.
With our custom hardware, but without the BMA400 connected, we measure a sleep current of approximately 1 µA. When only the BMA400 is connected (including its peripherals, capacitors, resistors, etc.), the power draw remains minimal at less than 5 µA.
However, when both the MCU and the BMA400 are connected, the sleep current jumps to 30 µA, despite data transmission and reception functioning normally and BMA's datasheet's suggested 14.5uA consumption.
During sleep, our MCU turns off VSS_IO of the BMA400 while keeping VDD_IO connected. The BMA400's interrupt pins are configured as active high, open-drain, while the MCU’s interrupt pins are set as pull-down.
Are these pin configurations optimal for minimizing power consumption? We have noticed that the interrupt pins seem highly susceptible to leakage. Additionally, our system operates at 3V–2V levels.
Best regards.