Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201052B • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice. • July 2, 2009

1

PRODUCT SUMMARY

SKY77546 Tx–Rx Front-End Module for Dual-Band

GSM / GPRS / EDGE

Applications

• Dual-band cellular handsets

encompassing

- Class 4 GSM900

- DCS1800

- Class 12 GPRS multi-slot

operation

- Linear EDGE operation

Features

• High efficiency

45% (GSM900)

40% (DCS1800)

• Current limiting for

protection and extended

battery life

• Input/Output internally

matched 50

Ω

• TX–VCO-to-antenna and

antenna-to-RX-SAW filter

RF interface

• TX harmonics below

–36 dBm

• Small, low profile package

- 7 mm x 6 mm x 0.9 mm

- 30-pad configuration

• Low APC current: 15 μA

Description

The SKY77546 is a transmit and receive Front-End Module (FEM) designed in a compact form factor

for dual-band cellular handsets comprising GSM900 and DCS1800 operation. The SKY77546 offers a

complete Transmit VCO-to-Antenna and Antenna-to-Receive SAW filter solution that supports Class

12 General Packet Radio Service (GPRS) multi-slot operation and EDGE operation for handsets and

modules.

The module consists of a GSM900 PA block and a DCS1800 PA block, impedance-matching circuitry

for 50

Ω input and output impedances, TX harmonics filtering, high linearity and low insertion loss RF

switches, and a Power Amplifier Control (PAC) block. A custom CMOS integrated circuit provides the

internal PAC function, external interface circuitry, and decoder circuitry to control the RF switches.

The integrated PAC function provides envelope amplitude control by reducing sensitivity to input drive,

temperature, power supply, and process variations. The Heterojunction Bipolar Transistor (HBT) PA

blocks are fabricated onto a single InGaP/GaAs die. One PA block supports the GSM900 band and the

other PA block supports the DCS1800 band. Both PA blocks share common power supply pads to

distribute current. The output of each PA block and the outputs to the two receive pads are connected

to the antenna pad through a diplexer and SP2T switch. The GaAs die, switch die, Silicon (Si) die, and

passive components are mounted on a multi-layer laminate substrate. The assembly is encapsulated

with plastic overmold.

Band selection and control of transmit and receive RF signal flows are performed using five external

control pads. The band select pad (BS) selects GSM or DCS modes of operation. The TxEN pad selects

receive or transmit mode of the respective RF switch (Tx = logic 1). SW_EN provides improved

isolation for flexibility in control timing to meet the required time mask. MODE configures the

amplifier for GMSK operation (MODE = 0) or linear EDGE operation (MODE = 1). Proper timing of the

logic on these pads, and Analog Power Control (APC) allows for high isolation between the antenna

and Tx-VCO while the VCO is being tuned prior to the transmit burst. Standby mode provides a low-

current consumption state. Low leakage current (6.5 μA, typical) of the dual PA module maximizes

handset standby time.

Figure 1. Functional Block Diagram