SKY77552 Datasheet, PDF (1/2 Pages) Skyworks Solutions Inc. – Quad-Band Tx / Dual-Band Rx iPAC FEM for GSM / GPRS (824-915 MHz and 1710-1910 MHz)

PRODUCT SUMMARY
SKY77552 Quad-Band Tx / Dual-Band Rx iPAC^™ FEM for
GSM / GPRS (824–915 MHz and 1710–1910 MHz)
Applications
• U.S. or Euro dual-band
cellular handsets
encompassing
- Class 4 GSM850/900
- DCS1800/PCS1900
- Class 12 GPRS multi-slot
operation
Features
• High efficiency
- 43.5% GSM
- 37.5% DCS/PCS
• Low transmit supply current
- 1.31 A GSM
- 0.96 A DCS/PCS
• 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
• PHEMT RF switches afford
high linearity, low insertion
loss, and less than 20 μA
supply current in receive
modes
• Small, low profile package
- 7 x mm 6 mm x 0.9 mm
• Compatible with multiple
logic families
• Low VRAMP current: 25 μA
Description
The SKY77552 is a quad-band transmit and dual-band receive front-end module (FEM) with
Integrated Power Amplifier Control (iPAC^™) for cellular handsets comprising GSM and DCS/PCS
operation. The FEM has quad-band capability in applications of U.S. or Euro dual-band platforms.
Designed in a low profile, compact form factor, the SKY77552 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 GSM PA block and a DCS/PCS 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 GSM band and the other PA
block supports the DCS/PCS 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. The band select pad (BS) selects between
GSM and DCS/PCS modes of operation. The transmit enable (TxEN) pad controls receive or transmit
mode of the respective RF switch (Tx = logic 1). Proper timing between transmit enable (TxEN) 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 SKY77552 is compatible with logic levels from 1.2 V to VCC for BS and TxEN 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
201167A • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice. • October 22, 2009
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