An IEEE 802.15.4z-Compliant Reconfigurable Pulse-Shaping UWB Digital Power Amplifier in 28-nm CMOS

In this article, a fully ON-chip current-mode digital power amplifier (C-DPA) for ultrawideband (UWB) transmitter that features reconfigurable pulse-shaping is presented. The proposed UWB pulse-shaping technique is implemented by the programmable delay lines to achieve high spectrum utilization and significant sidelobe suppression. An AM–AM calibration method is used to improve the linearity of the generated pulses. Furthermore, an ON-chip broadband output matching network (OMN) with a second-harmonic trap enables the entire chip to be implemented by thin-gate transistors without the risk of breakdown. As a proof-of-concept, a prototype is implemented in a 28-nm CMOS process with a supply voltage of 0.9 V. The measurement results comply with the physical requirement of the IEEE 802.15.4z standard. The chip can operate in channels from 4 to 9 GHz at various mean pulse repetition frequency (PRF) from 1 to 249.6 MHz. The designed pulse shaper enables reconfiguring pulse templates with a bandwidth from 0.5 to 1.33 GHz. The measured spectrum utilization is up to 58%/57% in band 9/11 with a bandwidth of 0.5/1.33 GHz and the measured sidelobe suppression above 30 dBr. The peak output power is 14.5 dBm, with a peak drain efficiency of 42% within the operating frequency range.