Title :
High performance open-loop AM modulator designed for power control of E-GPRS polar modulated power amplifier
Author :
Pehlke, David R. ; Hadjichristos, Aristotele ; Justice, Scott
Author_Institution :
Ericsson Mobile Platforms, Research Triangle Park, NC, USA
Abstract :
An E-GPRS power amplifier controller, designed in a 5 V 0.5 μm CMOS technology, is presented. Based on an open-loop polar modulation transmitter strategy for both GMSK in GSM and 8PSK in EDGE, the power control for both ramping and modulation depth is provided from collector supply control, and critical power amplifier (PA) temperature and process variability is compensated through the use of an automated bias calibration procedure detailed herein. Leveraging the architecture´s capability for removal of transmit SAW filters, removal of isolators and maintenance of critical adjacent channel power ratio (ACPR) and error vector magnitude (EVM) performance into PA output mismatched impedance environments, the controller provides excellent linearity for higher power 8PSK power, and performance of transient spectrum due to switching even when run into the battery headroom limit of the supply rail.
Keywords :
CMOS integrated circuits; UHF power amplifiers; cellular radio; minimum shift keying; modulators; packet radio networks; phase shift keying; 0.5 micron; 5 V; 8PSK; ACPR; CMOS; E-GPRS polar modulated PA; EDGE; EVM; GMSK; GSM; PA output mismatched impedance environments; adjacent channel power ratio; amplifier linearity; automated bias calibration procedure; cellular handset transmission; error vector magnitude; modulation depth; open-loop AM modulator; open-loop polar modulation transmitter; power amplifier controller; ramping control; Automatic control; CMOS technology; Calibration; GSM; High power amplifiers; Open loop systems; Power amplifiers; Power control; Temperature control; Transmitters;
Conference_Titel :
Custom Integrated Circuits Conference, 2004. Proceedings of the IEEE 2004
Print_ISBN :
0-7803-8495-4
DOI :
10.1109/CICC.2004.1358886
