I have a device that runs on voltage between 3v and 3v3 and consumes current anywhere between 4mA and 50mA. The device is powered from a battery with a 3v3 regulator.
I need to design a circuit that can switch on/off the device and I can not decide between a BJT and a mosfet for switching.
If I use a MMBT3904 npn transistor, I will have to keep base current at approximately 1mA so that It can drive the device at its maximum current consumption of 50mA (with a gain of 60). It seems like it would be very inefficient when only 4mA of current is required. Also there is the Vce voltage drop which the datasheet says can be 300mV at Ic=50mA. Voltage drop greater than 300mV will cause my device to malfunction.
As far as mosfet is concerned I can not seem to find a mosfet that can drive 50mA with Vgs of 3.3v.
My electronics is a little rusty and It does not seem to me helping me.