Fem With Integrated Power Amplifier Module; (Sky77550, U500); General Description - LG -A230 Service Manual

3. TECHNICAL BRIEF
3.3 FEM with integrated Power Amplifier Module (SKY77550, U500)
3.3.1 Internal Block Diagram
Figure. 3-3-1 SKY77550 FUNCTIONAL BLOCK DIAGRAM

3.3.2 General Description

Skyworks latest front-end modules (FEM) for GSM applications with integrated power amplifier control (iPAC™)
provide a high level of integration, high efficiency, ease of application, and smaller packaging.
The new BiFET control circuit improves the output RF spectrum and simplifies the calibration process.
This Application Note aids phone anufacturers with implementing the latest Skyworks SKY77550 iPAC™ Front-
End Module.
A Skyworks iPAC™ FEM consists of a PA lineup block, a PAcontrol block, impedance matching circuits,
harmonic filtering,and a switch. Embedded in a single Gallium Arsenide (GaAs) die,one Heterojunction Bipolar
Transistor (HBT) PA lineup supports theGSM850/900 bands and another supports the DCS1800 and PSC1900
bands.
A BiFET block provides the internal PAC function and interface circuitry. The front-end, with switches and
diplexer, provides a single antenna port and low insertion loss receive paths for two Rx ports.
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