A Wideband Digital Polar Transmitter with Integrated Capacitor-DAC-Based Constant-Envelope Digital-to-Phase Converter

This paper presents a wideband digital polar transmitter (DPTX) with integrated capacitor-DAC-based constant-envelope digital-to-phase converter (DPC). The switched-capacitor DAC topology is adopted to improve the linearity. The harmonic rejection and cell-reused techniques are employed to reject the 3rd/5th-order harmonics and reduce the power consumption, respectively. The measurement results of DPC demonstrate the maximum INL and DNL of 1 and 0.8 degrees with the power consumption of 12.7mW@1.5GHz. The DPTX obtains the peak output power of 20.1dBm with 23.7% system efficiency and wideband frequency coverage over 1.2-2.5GHz with only 0.7dB power variation. When amplifying a 10MHz 64QAM LTE signal at 1.5GHz, it achieves -28.6dB EVM and 15.2% system efficiency at 15.0dBm average output power.

[1]  Kathleen Philips,et al.  26.3 A 1.3nJ/b IEEE 802.11ah fully digital polar transmitter for IoE applications , 2016, 2016 IEEE International Solid-State Circuits Conference (ISSCC).

[2]  Ashoke Ravi,et al.  2.9 A 2GHz 244fs-resolution 1.2ps-Peak-INL edge-interpolator-based digital-to-time converter in 28nm CMOS , 2016, 2016 IEEE International Solid-State Circuits Conference (ISSCC).

[3]  Chih-Kong Ken Yang,et al.  A 0.1-1.5 GHz 8-bit inverter-based digital-to-phase converter using harmonic rejection , 2013, 2012 IEEE Asian Solid State Circuits Conference (A-SSCC).

[4]  Hao Min,et al.  4.2 A Broadband Switched-Transformer Digital Power Amplifier for Deep Back-Off Efficiency Enhancement , 2019, 2019 IEEE International Solid- State Circuits Conference - (ISSCC).

[5]  Ali M. Niknejad,et al.  Design Considerations for a Direct Digitally Modulated WLAN Transmitter With Integrated Phase Path and Dynamic Impedance Modulation , 2013, IEEE Journal of Solid-State Circuits.

[6]  Hyung Seok Kim,et al.  13.6 A 2.4GHz WLAN digital polar transmitter with synthesized digital-to-time converter in 14nm trigate/FinFET technology for IoT and wearable applications , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[7]  Peter Asbeck,et al.  A wideband voltage mode Doherty power amplifier , 2016, 2016 IEEE Radio Frequency Integrated Circuits Symposium (RFIC).

[8]  Kathleen Philips,et al.  A 1.3 nJ/b IEEE 802.11ah Fully-Digital Polar Transmitter for IoT Applications , 2016, IEEE Journal of Solid-State Circuits.