I am designing a IoT PCB that will be powered with a Li-ion battery. I need to be really thoughtful about how much current will be drawn by the entire circuit, in order to increase battery life.
I've got 4 signals to and from the MCU that needs to go be inverted:
- /CS pin of SPI communication (5MHz, 200ns period)
- /INT interrupt output of a device
- /SIGNAL of a pushbutton
- CTRL control signal of a device
I need to invert these signals because my MCU can only be woken up from sleep by rising edge/high level GPIOs, so software inversion is not an option.
What would be the best way to invert these signal while being mindful of power consumption, size, and cost? Usign a NPN transistor? Using a N-channel MOSFET? or using a dedicated inverter logic gate chip?
Initially I designed a NPN inverter circuit with a mmbt2222 but the value of the base resistors, collector pull-up, and input pull-up or pull-down had a massive negative effect on power consumption.
Thank you all