A 1.9nJ/bit, 5Mbps multi-standard ISM band wireless transmitter using fully digital PLL

This paper presents an energy efficient transmitter for multi-standard applications (IEEE802.15.4, BLE, 5Mbps) in ISM2.4GHz band. It incorporates a fully digital PLL with two point modulation to achieve upto 5Mbps data rate at 9.5mW power consumption (including all power management blocks) at 0dBm output power, leading to 1.9nJ/b efficiency. The proposed digital PLL uses a counter based area and power efficient re-circulating TDC, current reuse low area DCO using resistive tail, process compensated high speed divider, class-AB PA stages, and fully integrated on-chip LDOs. The entire transmitter occupies 0.35mm2 Silicon area in a 65nm digital CMOS process.