SKY77551数据手册Skyworks中文资料规格书

描述 Description

Please note: this product is being discontinued and is not recommended for new designs.

SKY77551 is a transmit and receive Front End Module (FEM) designed in a very low profile(0.9 mm) and compact form factor for quad-band cellular handsets comprising GSM850/900,DCS1800, and PCS1900 operation — a complete transmit VCO-to-Antenna and Antenna-toreceiveSAW filter solution. The FEM also supports Class 12 General Packet Radio Service(GPRS) multi-slot operation and linear EDGE operation. WCDMA switch-through support isprovided by three dedicated high-linearity ports.

The module consists of a GSM850/900 PA and DCS1800/PCS1900 PA block, impedancematchingcircuitry for 50 Ω input and output impedances, Tx harmonic filtering, a highlinearity/low insertion loss switch, and a CMOS Power Amplifier Control (PAC) block. A customsilicon integrated circuit contains decoder circuitry to control the RF switch while providing alow current, external control interface.

Fabricated in InGaP/GaAs, the Heterojunction Bipolar Transistor (HBT) PA blocks support theGSM850/900 bands and DCS1800/PCS1900 bands. Both PA blocks share common powersupply pads to distribute current. The output of the PA block and the outputs to the sevenreceive pads connect to the antenna pad through a high-linearity antenna switch. The WCDMAand Rx ports feature a 0 volts DC offset level which eliminates the need for external blockingcapacitors. The InGaP/GaAs die, switch die, Silicon (Si) controller die, and passive componentsare mounted on a multi-layer laminate substrate and the entire assembly is encapsulated withplastic overmold.

RF input and output ports of the SKY77551 are internally matched to a 50 Ω load to reduce thenumber of external components on the phone board. Extremely low leakage current of the FEMmaximizes handset standby time. Control of transmit and receive RF signal flows, and bandselection are performed by four external control pads (see Figure 1 on overleaf). Mode ofoperation, Tx vs. Rx, and Band (GSM850, GSM900, DCS1800, and PCS1900) are controlledwith the four logic inputs: Mode, TxEN, BS1, and BS2. Proper timing of the TxEN input and theVRAMP input ensures high isolation between the antenna and Tx-VCO while the VCO is beingtuned prior to the transmit burst. All logic control inputs returned to a standby state (0 V)ensure ETSI compliance to the harmonics specification.

The integrated power amplifier control (PAC) function provides envelope amplitude control byreducing sensitivity to input drive, temperature, power supply, and process variation. Outputpower variation into mismatch is minimized with Skyworks’ True Power control circuit.

特性 Features

• Small, low profile package: 6 mm x 6 mm x 0.9 mm, 28-pad configuration
• Low input power range: –1 to 6 dBm
• High efficiency: 45% GSM850, 45% GSM900, 40% DCS1800, 40% PCS1900
• Tx-VCO-to-antenna and antenna-to-Rx-SAW filter RF interface
• Tx harmonics below –38 dBm
• Current limiting for over-voltage protection and extended battery life
• Input/Output matched internally to 50 Ω
• High impedance control inputs: 20 μA, maximum
• Input control circuitry built-in for improved TRP variation