We developed MHz-range oscillators (e.g., crystall oscillator, relaxation oscillator, etc.) and temperature sensors for low-voltage and ultra-low-power IoT radio. The oscillator and temperature sensor are indispensible circuits module for the IoT radio. The former can be used as frequency reference to provide accurate timing signals that synchronize the functions of various electronic components, and the latter is critical for monitoring the temperature of the environment in which the IoT device is located. Moreover, energy-harvested IoT devices are promising for perpetual operations. Yet, the energy harvester usually has output voltage <0.5V, which calls for additional voltage converter for circuits powered by standard VDD (>1V). Hence, we aim in developing MHz-range oscillators and temperature sensor with low VDD for IoT radio. For further detail, please check our papers from ISSCC'18, JSSC'18, JSSC'21, ISSCC'23, JSSC'23.