RMPA2271

The RMPA2271 Power Amplifier Module (PAM) is Fairchild's latest innovation in 50?  matched, surface mount modules targeting WCDMA/UMTS applications. Answering the call for integrated Power Detection, the RMPA2271 offers the ability to measure power output over a 20dB range.This feature eliminates the need of an external power detector and lossy directional coupler, improving system perfomance and reducing overall cost. Simple two-state Vmode control is all that is needed to change the PA optimization from high power to low power mode to minimize current usage. The 3 x 3 x 1.0mm LCC package fits into the tightest spaces available on handset boards and is footprint compatible with existing 3 x 3mm LCC power amplifiers. The multi-stage GaAs Microwave Monolithic Integrated Circuit (MMIC) is manufactured using Fairchild's InGaP Heterojunction Bipolar Transistor (HBT) process.

Features of the RMPA2271 are:(1)temperature compensated, integrated power detector with >20dB dynamic range; (2)41% WCDMA efficiency at +28dBm average output power 19201980MHz; (3)meets UMTS/WCDMA and HSDPA performance requirements ; (4)compact lead-free compliant LCC package(3.0 x 3.0 x 1.0 mm nominal); (5)single positive-supply operation and low power and shutdown modes; (6)low Vref (2.85V) compatible with advanced  handset chipsets; (7)internally matched to 50 and DC blocked RF input/output.

The absolute maximum ratings of the RMPA2271 can be summarized as:(1)supply voltages:5.0V;(2)storage temperature range:-55 to 150;(3)reference voltage:2.6 to 3.5 V;(4)power control voltage:3.5 V;(5)RF Input Power:+10 dBm.Due to the varying amplitude envelope of WCDMA signal, a filter is required at the Pdet pin in order to minimize the ripple noise of the detector output voltage (Pdet). RMPA2271 has no integrated filter for the Pdet pin.Therefore, an external low-pass filter, comprising a shunt resistor (R) and a shunt capacitor (C), is required to detect the WCDMA signal properly. The filter bandwidth is determined by the RC time constant of the filter, and can be reduced by increasing the values of the resistor and/or capacitor. A narrower filter bandwidth has the advantage of lower voltage ripple noise, but it comes at the expense of increased response time. A tradeoff needs to be made between the ripple noise and response time for the optimal system performance.