This book guides the reader through the design of circuits and wireless IoT devices deployed in applications demanding low power, small size, and high levels of integration. The design of a sub-1V wireless-LAN receiver is detailed along with associated calibration algorithms. Some of the key circuits detailed include a successive approximation analog-to-digital converter, a rail-to-rail comparator, a digitally programmable CMOS low-noise amplifier, an RF voltage to current converter, and a fifth-order Chebyshev analog programmable filter. Helpful appendices are included teaching operational amplifier design, CMOS and SiGe low-noise amplifier design, impedance matching, noise and distortion analysis. While theory and design equations are presented throughout the book for the various circuit designs, practical implementation and design tradeoffs are emphasized so the reader can immediately apply knowledge gained. Receiver and calibration circuits are designed in a standard CMOS technology using a 900mV power supply.