LG PRADA KE850 - Troubleshooting Common Issues; SIM and Network Issues; Code and Function Issues; Call and Power Issues

3. TECHNICAL BRIEF
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3.27. Power Amplifier Module
The SKY77340 (U404) designed in a compact form factor for quad-band cellular handsets comprising
GSM850/900,DCS1800,PCS1900, supporting GMSK and linear EDGE modulation. The module
consists fo a GSM850/900 PA block and a DCS1800/PCS1900 PA block, impedance-matching
circuitry for 50 ohms input and output impedances, and a Multi-function Power Amplifier Control(MFC)
block. Two separate Heterojunction Bipolar Transistor9HBT) PA blocks are fabricated onto InGaP die.
One supports the GSM850.900 bands, the other supports the DCS1800 and PCS1900 bands. Both
PA blocks share common power supply pins to distribute current. RF input and output ports are
internally matched to 50 ohms to reduce the number of external components.
Table 13 PAM pin description
PIN Name Description
1 MODE GMSK/EDGE Power control mode. L=GMSK, H=EDGE
2 DCS/PCS_IN RF input(DCS/PCS) DC Blocked
3 BS Band Select
4 REVD1 Reserved
5 VBATT DC Supply
6 VRAMP
Analog PA Bias Control(All Bands, EDGE Mode)
Analog Output Power Control(All Bands, GMSK Mode)
7 GSM_IN RF input(EGSM) DC Blocked
9 GSM_OUT RF Output(EGSM) DC Blocked
10,11 GND Ground
12 REVD2 Reserved
13,14,15 GND Ground
16 DCS/PCS_OUT RF Output(DCS/PCS) DC Blocked
Pad GND PAD GRID Ground pad grid is device underside.