SKY77544 Datasheet, PDF (1/2 Pages) Skyworks Solutions Inc. – Wideband envelope control path

PRODUCT SUMMARY
SKY77544 Tx-Rx FEM for Quad-Band GSM / GPRS / EDGE –
Triple-Band WCDMA Antenna Switch Support
Applications
• Quad-band cellular handsets
encompassing
- Class 4 GSM850/900
- Class 1 DCS1800 PCS1900
- Class 12 GPRS
multi-slot operation
- EDGE polar modulation
- Triple band WCDMA antenna
switch support
Features
• Small, low profile package
- 6 mm x 6 mm x 0.9 mm
- 28-pad configuration
• Low input power range
- 0 to 6 dBm
• High efficiency
- GSM850 41%
- GSM900 41%
- DCS 40%
- PCS 40%
• Tx-VCO-to-antenna and
antenna-to-Rx-SAW filter RF
interface
• Tx harmonics below -38 dBm
• Wideband envelope control path
• Input/Output matching 50 Ω
internal
• Low APC current
20 μA
• High impedance control inputs
15 μA, typical
• Integrated module temperature
sensor
Description
SKY77544 is a transmit and receive Front End Module (FEM) designed in a very low profile
(0.9 mm), compact form factor for quad-band cellular handsets comprising GSM850/900,
DCS1800, and PCS1900 operation — 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 and EDGE Polar Modulation. WCDMA switch-through support is
provided by three dedicated high-linearity ports.
The module consists of a GSM850/900 PA and DCS1800/PCS1900 PA block, impedance-
matching circuitry for 50 Ω input and output impedances, Tx harmonic filtering, high linearity-
low insertion loss switches, and a CMOS Power Amplifier Control (PAC) block. A custom silicon
integrated circuit contains decoder circuitry to control the RF switch while providing a low
current external control interface. An integrated temperature sensor provides an analog voltage
based on the temperature of the module.
Fabricated in InGaP/GaAs, the Heterojunction Bipolar Transistor (HBT) PA blocks support the
GSM850/900 bands and DCS1800/PCS1900 bands. Both PA blocks share common power
supply pads to distribute current. The output of the PA block and the outputs to the seven
receive pads connect to the antenna pad through a highly linear antenna switch. The WCDMA
and Rx ports feature a near 0 volts DC offset level, which eliminates any need for external
blocking capacitors. The InGaP/GaAs die, switch die, Silicon (Si) controller die, and passive
components are mounted on a multi-layer laminate substrate and the entire assembly is
encapsulated with plastic overmold.
RF input and output ports of the SKY77544 are internally matched to a 50 Ω load to reduce the
number of external components for a quad-band design. Extremely low leakage current of the
FEM maximizes handset standby time. Band selection and control of transmit and receive RF
signal flows are performed by use of four external control pads. See Figure 1 shown on
overleaf. Mode of operation Tx, Rx, Band (GSM850, GSM900, DCS, PCS, and UMTS) is
controlled with 4 logic inputs: BS1, BS2, Mode, and TxEN. Proper timing of the TxEN input and
the VAPC input ensures high isolation between the antenna and Tx-VCO while the VCO is being
tuned prior to the transmit burst. The Enable input controls the initial turn-on of the PAC
circuitry to minimize battery drain.
The integrated power amplifier control (PAC) function provides envelope amplitude control by
reducing sensitivity to input drive, temperature, power supply, and process variation.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201259A • Skyworks Proprietary and Confidential Information • Products and Product Information are Subject to Change Without Notice. • March 12, 2010