The TPL5010 Nano Timer is an ultra-low power timer with a watchdog feature designed for system wake up in duty-cycled, battery-powered applications such as those in IoT. Many of these applications require the use of a µC, so it is desirable to keep the µC in a low power mode to maximize current savings, waking up only during certain time intervals to collect data or service an interrupt. Although the internal timer of the µC can be used for system wake-up, it can single-handedly consume microamps of total system current. Consuming only 35 nA, the TPL5010 can replace the functionality of the integrated µC timer. This allows the µC to be placed in a much lower power mode, with the internal timer off, returning only to active mode upon an interrupt by the TPL5010. By offering power savings of almost two orders of magnitude, the TPL5010 enables the use of significantly smaller batteries for energy harvesting or wireless sensor applications. The TPL5010 provides selectable timing intervals from 100 ms to 7200 s and is designed for interrupt-driven applications. Some standards (such as EN50271) require implementation of a watchdog for safety and the TPL5010 realizes this watchdog function at almost no additional power consumption. The TPL5010 is available in a 6-pin SOT23 package.