LG KU250 Service Manual - Page 29
GSM PAM U101 : SKY77318
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3. TECHNICAL BRIEF 3.5.5 GSM PAM (U101 : SKY77318) The SKY77318 is an extremely small (6 x 6 mm), GSM PAM for handset applications. This module has been optimized for excellent efficiency and Pout while maintaining high GSM/GPRS efficiency. The small size and high performance is achieved with high-reliability GaAs HBT technology. With 50Ω and output, no external matching or bias components are required. The module incorporates two highly-integrated GaAs power amplifier die with a BiCMOS controller. Each amplifier has three gain stages with on-die inter-stage matching implemented with a high Q passives technology for optimal performance. The CMOS controller implements a fully integrated power control within the module for GSM operations, and serves as the GPRS operations. This eliminates the need for any external couplers, power detectors, current sensing etc., to assure the output power level. The module has Tx enable and band select inputs. Module construction is a lowprofile overmolded land-grid array on laminate. L115 18nH C124 100p Rev.D L403 1.5nH L116 10nH C123 0.01u C121 33u +VPWR 100ohm R107 C137 NA C441 5.6p C438 100p C138 NA C139 68p C134 0.01u C136 0.01u GSM_PA_RA EGSM NA L111 5.6nH L406 2.7nH 8.86dB Rev.1.0 R108 51 DCS_PCS_TX 91 R110 91 R111 VAPC 20 VBATT 17 VCC1B 6 VCC1A 2 15 DCS_PCS_OUT 3 DCS_PCS_IN U101 11 EGSM_OUT EGSM_IN 4 19 RSVD_GND ENABLE 18 21 P_GND SKY77318 BS 1 FL101 R113 100ohm C149 15p GSM_PA_EN 45 O1 G3 1 IN G2 G1 32 EFCH897MTDB1 7.5dB R112 39 7 GND1 8 GND2 GND4 GND3 10 GND5 12 GND6 13 GND7 GND8 GND9 5 9 16 14 R117 100ohm C153 15p GSM_PA_BAND GSM_PA_BAND MODE LOW HIGH GSM DCS/PCS R114 100ohm R115 100ohm GSM_TX [Figure 1. 8] GSM PAM Schematic - 30 -