Only For Training And Service Purposes - LG -S310 Service Manual

3.2.3 Power Amplifier Module(SKY77336)
SKY77336 Power Amplifier Module (PAM) is designed in a compact form factor for quad-band cellular
handsets comprising GSM850/900, DCS1800 and PCS1900, supporting Gaussian Minimum-Shift Keying
(GMSK) and Polar Enhanced Data for GSM Evolution (EDGE) modulation. Class 12 General Packet Radio
Service (GPRS) multi-slot operation is also supported.
The module consists of GSM850/900 PA and DCS1800/PCS1900 PA blocks, impedance matching circuitry for
50 Ω input and output impedances, and a Power Amplifier Control (PAC) block. The custom CMOS integrated
circuit provides the internal PAC function and interface circuitry. 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 InGaP/GaAs 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 SKY77336 are internally matched to a 50 Ω load to reduce the number of
external components for a quad-band design. Extremely low leakage current(10 μA, typical) of the PAM
module maximizes handset standby time.
The SKY77336 also contains band-select switching circuitry to select GSM (logic 0) or DCS/PCS (logic 1) as
determined from the Band Select (BS) signal. See Figure shown below.
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Only for training and service purposes

[Figure 3.2.3-1] PAM functional Block diagram
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3. TECHNICAL BRIEF
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