The term “the Internet of Things” was first used in 1999 to refer to a network of objects embedded with sensors and wireless connectivity. By 2015, there were 5 billion of these connected devices. Within the next five years, it is predicted that there will be more than 25 billion connected IoT devices. This rapid market growth has been made possible by many innovations in connectivity standards, system architecture, power management, and circuit design. This talk will describe seven different design challenges and the solutions that have been needed for the creation of today's low power, small size, and low cost wireless sensors nodes. These challenges include reducing sleep current, improving power management efficiency, improving the sleep timer frequency stability, reducing startup time, connectivity standard optimization, reducing active power, and removing external components. The impact of each improvement to the over all system performance will be described, as well as examples of state-of-the-art designs in each of these areas. Further advances that are needed to continue this market growth will also be presented.