A 1-Mbps 0.7-nJ/Bit Low-Complexity High-Robust FM-UWB Transmitter Under a Sub-1-V Supply

A frequency-modulated ultra-wideband (FM-UWB) transmitter is fabricated in 65-nm CMOS, to feature high data rate, high energy efficiency, low complexity, and high robustness. A dual-modulus divider with duty-cycle correction and a square-to-triangular converter with a common-mode feedback unit, are for subcarrier generation. A dual-path ring current-controlled oscillator is for linear FM, and followed by a high-robust small-sized power amplifier. An all-digital automatic frequency control loop calibrates the carrier frequency. Experimental results show that the 3.75-4.25 GHz transmitter generates an FCC-compliant UWB signal, and has an energy efficiency of 0.7 nJ/bit under a data rate of 1 Mbps and a sub-1-V supply, with an active area of 0.14 mm2 and phase noise of –77 dBc/Hz at 1-MHz offset, as well as an output power of –14.3 dBm. Especially, both the subcarrier generator and the PA are different from the existing literature.