- 17 -
Copyright © 2010 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. TECHNICAL BRIEF
snTzZXWGGG
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.
[Figure 3.2.3-1] PAM functional Block diagram