A 130-nm CMOS 0.007- $\hbox {mm}^{2}$ Ring-Oscillator-Based Self-Calibrating IR-UWB Transmitter Using an Asynchronous Logic Duty-Cycled PLL

We present a 0.007 mm² impulse-radio ultrawideband transmitter (TX) based on a ring oscillator capable of synthesizing pulses with both controlled center frequency and bandwidth using a single duty-cycling/trigger reference input. The TX embeds a single-phase charge-pump phase-locked loop (PLL), implemented with asynchronous logic, with 55 logic elements overall. The system, including radio frequency output buffers, consumes measured 30-45 pJ/pulse with a measured efficiency of ~ 47% at 285 MHz center frequency and V_dd in the range of 0.97-1.17 V. At 1.2V supply, the 130 nm CMOS TX tolerates ± 10% V_dd variation, maintaining robust lock and controlled power spectral density (PSD) at 300 MHz center frequency, -19 dBm radiated power at 1 MHz pulse-repetition frequency, and a fractional bandwidth of 0.23. At 300 MHz, the system achieves a measured 100 ps RMS jitter, and without output buffers, the sole PLL logic occupies an active silicon area of 0.0045 mm².