SKY77543 Datasheet, PDF (1/2 Pages) Skyworks Solutions Inc. – Tx - Rx iPAC FEM for Dual-Band GSM / GPRS (824 - 849 MHz), (1850 - 1910 MHz)

PRODUCT SUMMARY
SKY77543 Tx–Rx iPAC^™ FEM for Dual-Band GSM / GPRS
(824–849 MHz), (1850–1910 MHz)
Applications
• Dual-band cellular handsets
encompassing
- Class 4 GSM850
- PCS1900
- Class 12 GPRS multi-slot
operation
Features
• High efficiency
- GSM850 45.0%
- PCS1900 38.5%
• Low transmit supply current
- GSM850 1.26 A
- PCS1900 0.93 A
• Internal ICC sense resistor
for iPAC
• Closed loop iPAC
• 50 Ω matched Input/Output
• Tx–VCO-to-antenna and
antenna-to-Rx-SAW filter
RF interface
• Tx harmonics below
–33 dBm
• PHEMT RF switches afford
high linearity, low insertion
loss, and less than 20 μA
supply current in receive
modes
• Small outline: 7 x 6 mm
• Low profile: 0.9 mm
• Compatible with multiple
logic families
• Low APC current: 25 μA
Description
The SKY77543 is a transmit and receive front-end module (FEM) with Integrated Power Amplifier
Control (iPAC^™) for dual-band cellular handsets comprising 850 and PCS1900 operation. Designed in
a low profile, compact form factor, the SKY77543 offers a complete Transmit VCO-to-Antenna and
Antenna-to-Receive SAW filter solution. The FEM also supports Class 12 General Packet Radio
Service (GPRS) multi-slot operation.
The module consists of a GSM850 PA block and a PCS1900 PA block, impedance-matching circuitry
for 50 Ω input and output impedances, Tx harmonics filtering, high linearity and low insertion loss
PHEMT RF switches, diplexer and a Power Amplifier Control (PAC) block with internal current sense
resistor. A custom BiCMOS integrated circuit provides the internal PAC function and decoder circuitry
to control the RF switches. The two Heterojunction Bipolar Transistor (HBT) PA blocks are fabricated
onto a single Gallium Arsenide (GaAs) die. One PA block supports the GSM850 band and the other PA
block supports the PCS1900 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 PHEMT RF switches and a diplexer. The GaAs die, PHEMT 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 modes are performed using two external control
pads. Refer to the functional block diagram in Figure 1 below. The band select pad (BS) selects
between GSM and PCS modes of operation. The transmit enable (Tx_EN) pad controls receive or
transmit mode of the respective RF switch (Tx = logic 1). Proper timing between transmit enable
(Tx_EN) and Analog Power Control (VRAMP) allows for high isolation between the antenna and Tx-VCO
while the VCO is being tuned prior to the transmit burst.
The SKY77543 is compatible with logic levels from 1.2 V to VCC for BS and Tx_EN pads, depending
on the level applied to the VLOGIC pad. This feature provides additional flexibility for the designer in
the selection of FEM interface control logic.
Figure 1. Functional Block Diagram
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201036A • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice. • February 17, 2009
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