ABSTRACT
Ultra-low-power (ULP) short-range radios are the key enabler of a wide variety of Internet-of-Things (IoT) products such as wearable/implantable healthcare monitoring. This chapter discusses the design of ULP transmitters for Zigbee/Bluetooth Low Energy standard from system architecture to circuit techniques. It presents a case study of a 2.4-GHz transmitter using a function-reuse Class-F digitally controlled oscillator power amplifier (DCO-PA) achieving 22.6% system efficiency at 6-dBm Pout. The chapter analyses all-digital phase-locked loop to stabilize the DCO-PA frequency during the data transmission. Now around 5 billion people over the world use the wireless communication services. On the other hand, the number of articles over the world is much larger. Connecting all these articles together and linking them to the cloud will create a huge market for the electronic devices and semiconductor chips. People forecast that the number of IoT terminals will exceed 50 billion in the next 10 years, which is ten times of the mobile users today.
