SKY77523

• High efficiency
• Integrated coupler and switch
• Wideband envelope control path
• Input/output matching
• Small outline, low profile

Tx/Rx Front-End Module with Integrated Coupler for Quad-Band GSM and EDGE Applications

The SKY77523 is a transmit/receive Front-End Module (FEM)designed for Skyworks Helios? II-Plus EDGE RF Subsystem. Thissubsystem is intended for multi-band Global System for MobileCommunications (GSM), General Packet Radio Service (GPRS),and Enhanced Data Rate for GSM Evolution (EDGE) handsets andmodules. This subsystem supports GSM850, EGSM900,DCS1800, and PCS1900 applications.

The SKY77523 provides a complete transmit Voltage-ControlledOscillator (VCO)-to-antenna and antenna-to-receive SurfaceAcoustic Wave (SAW) filter solution.

The module SKY77523 consists of a single GSM850/EGSM900 andDCS1800/PCS1900 PA block, a PA Control (PAC) block,impedance-matching circuitry for 50 inputs and outputs,transmit harmonic filtering, an integrated coupler, high-linearityand low insertion-loss pHEMT RF switches, and a diplexer. Acustom CMOS integrated circuit SKY77523 provides the internal PACfunction, interface circuitry, and decoder circuitry to control theRF switches.

Two Heterojunction Bipolar Transistor (HBT) PA blocks of SKY77523 arefabricated onto an Indium Gallium Phosphide (InGaP) die; oneblock supports the GSM850 and EGSM900 bands, the othersupports the DCS1800 and PCS1900 bands. Both PA blocks sharecommon power supply pads to distribute current. Outputs fromthe PA blocks and the four receive pads connect to the antennausing pHEMT RF switches and the diplexer. The InGaP die, theSilicon (Si) die, the pHEMT die, and the passive components SKY77523 are mounted on a multi-layer laminate substrate, and the entireassembly encapsulated with plastic overmold.

Three external control pins facilitate band selection, and control ofthe transmit and receive RF signal flows. Pin signals BS0 and BS1select GSM, DCS, or PCS modes. The TR_EN pin signal selectstransmit or receive mode of the respective RF switch. Propertiming of the pin signal logic and power control (the VPC pin)allows high isolation between the antenna and the transmit VCOwhile the VCO is being tuned before the transmit burst.The PAC_EN signal enables the PAC circuitry to minimize batterydrain. The low leakage current (6.5 A, typical) of the dual PA module SKY77523 maximizes handset standby time.

The SKY77523, together with the SKY74138 RF transceiver, formthe Helios II-Plus EDGE RF Subsystem. Feedback signals from theSKY77523 to the SKY74138 form an integral portion of theSkyworks Polar Loop? architecture. This architectureautonomously splits amplitude and phase using the traditionalanalog In-Phase and Quadrature (I/Q) signals. The filter-savingadvantage of the translation-loop approach is embedded in thearchitecture. Also included is an AM loop that provides both signalAM and power level control.

The SKY77523 is packaged in a small, 34-pin 6 x 8 mm Multi-Chip Module (MCM) package.

Please note: SKY77523-13 is being discontinued and is not recommended for new design.