The TPL5110 nano timer from Texas Instruments is a low-power timer with an integrated MOSFET driver ideal for power gating in duty-cycled or battery-powered applications. Consuming only 35 nA, the TPL5110 can enable the power supply line and drastically reduce the overall system stand by current during sleep cycles, taking care of turning projects on/off using a built-in timer. Adafruit has created a breakout board to easily utilize these power savings which enable the use of significantly smaller batteries making it well-suited for energy harvesting or wireless sensor application development. The TPL5110 provides selectable timing intervals from 100 ms to 7200 s, adjustable using the on-board trim pot: nearly-all-the-way-to-the-left is "once per 100 ms" and all-the-way-to-the-right is "once every 2 hours". Essentially, the TPL will turn on periodically, adjustable by potentiometer or resistor, and turn on the project's power. It will then wait until a signal is received from the project to tell the TPL that it can safely turn off the power.

In addition, the TPL5110 has a unique One-shot feature where the timer will only power the MOSFET for one cycle. Adafruit’s breakout board makes use of this by allowing users to activate the TPL by pressing the onboard tactile switch or by triggering the Delay pin.

With Adafruit's TPL5110, breakout board usage is easy. Set the desired delay by adjusting the on-board trim pot, connect V_DD up to a 1.8 V to 5 V power supply, connect the project's power-in to the drive-pin, and, finally, connect a signal pin from the project to the done-pin to set the done-pin high when the project has completed the desired tasks.