Title :
High efficiency 450W asymmetric three-device Doherty amplifier with digital feedback predistortion
Author :
Staudinger, Joseph ; Bouisse, Gerard ; Kinney, John
Author_Institution :
Freescale Semicond., Tempe, AZ, USA
Abstract :
An asymmetric Doherty power amplifier based upon a three-device architecture for improved efficiency performance under extended power backoff operation is presented. The topology provides significant advantages in easing input/output matching constraints inherent in asymmetric Doherty amplifiers where the asymmetry necessitates unequal device geometries for the peaking and carrier sub-amplifier circuits. Excellent high efficiency performance (45% @ 8 dB power back-off) is demonstrated by implementing the Doherty amplifier using an advanced prototype LDMOS device technology developed at Freescale Semiconductor. The amplifier achieves a saturated output power greater than 450W at 2.14 GHz when biased with a 28V supply. When driven with a single carrier W-CDMA signal, an efficiency of 45% is achieved at 8 dB power back-off. Moreover, when linearized with a digital feedback pre-distorter the amplifier achieves an ACPR better than -55 dB.
Keywords :
MIS devices; distortion; power amplifiers; ACPR; LDMOS device technology; asymmetric three-device Doherty amplifier; carrier sub-amplifier circuits; digital feedback predistortion; freescale semiconductor; frequency 2.14 GHz; power 450 W; power back-off operation; single carrier W-CDMA signal; three-device architecture; voltage 28 V; Circuit topology; Feedback; Geometry; High power amplifiers; Impedance matching; Operational amplifiers; Power amplifiers; Predistortion; Prototypes; Semiconductor optical amplifiers; Doherty power amplifier; digital pre-distortion; efficiency enhancements;
Conference_Titel :
Radio and Wireless Symposium (RWS), 2010 IEEE
Conference_Location :
New Orleans, LA
Print_ISBN :
978-1-4244-4725-1
Electronic_ISBN :
978-1-4244-4726-8
DOI :
10.1109/RWS.2010.5434115
