LGE Internal Use Only
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Only for training and service purposes
3.2 Power Amplifier Modul(SKY77517)
The SKY77517 is a transmit and receive front_end module(FEM) with integrated Power Amplifier
Control for dual_band cellular handsets comprising GSM850 and PCS 1900 Operation. Designed in a
low profile, compact form factor, the SKY77517 offers a complete transmit VCO-to Antenna and
Antenna-to-Receive SAW filter solution.
The module consists of a GSM850 PA block and a PCS1900 PA block, impedancematching circuitry
for 50ohm 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.
3. TECHNICAL BRIEF
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Figure. 3-2 SKY77517 FUNCTIONAL BLOCK DIAGRAM