I would like to isolate a sensor supply voltage circuit during arduino sleep mode as the sensor (soil moisture) draws unnecessary current during the sleep cycle. Sensors are powered by 3.3V. I need to have a very low voltage drop across the isolation switch in the sensor supply voltage circuit. Switch is controlled by an arduino digital pin. I would like to maintain the 3.3V supply for the sensor when the switch is on. What are good options? Transistor has too large drop-out voltage. Analog switch? JFET? Please help, thank you.