A 3×3mm2 LTE/WCDMA dual-mode power amplifier module with integrated high directivity coupler

This paper presents a 1920–1980MHz LTE/WCDMA GaAs HBT/pHEMT-based 3×3mm2 power amplifier module (PAM) with integrated directional coupler targeted for mobile handset applications. The PA operates in two power modes with a dual-path structure. Each path is optimized individually for each power mode, achieving low DC quiescent current and significant current saving compared to single-mode PAs under power backoff. Bias current and load impedance are specifically optimized for linear operation under high peak-to-average ratio LTE modulation. The PAM achieves a low quiescent current of 8mA. Under LTE modulation, the PAM exhibits 38/24% PAE at 27.5/16dBm Pout at UTRA ACLR1<−39dBc. Under WCDMA modulation, the PAM attains 42/26% PAE at 28.5/17dBm Pout at ACLR1<−40dBc. Further current saving is demonstrated with the use of variable power supply. The integrated 20dB coupler achieves ±0.06dB coupling variation under VSWR 2.5∶1 mismatch, corresponding to a directivity of 36dB.

[1]  D.A. Teeter,et al.  Average current reduction in (W)CDMA power amplifiers , 2006, IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, 2006.

[2]  Gary Zhang,et al.  Dual mode efficiency enhanced linear power amplifiers using a new balanced structure , 2009, 2009 IEEE Radio Frequency Integrated Circuits Symposium.

[3]  Yang Li,et al.  A compact high directivity coupler with ±0.15dB error under VSWR 2.5∶1 for 3×3mm2 UMTS power amplifier modules , 2010, 2010 IEEE Radio and Wireless Symposium (RWS).

[4]  T. Arell,et al.  InGaP-Plus - A major advance in GaAs HBT Technology , 2006, 2006 IEEE Compound Semiconductor Integrated Circuit Symposium.

[5]  G. Hau,et al.  A 3x3mm2 embedded-wafer-level packaged WCDMA GaAs HBT power amplifier module with integrated Si DC power management IC , 2008, 2008 IEEE Radio Frequency Integrated Circuits Symposium.