蜂窝式手机中的噪声控制0.35 V ( IF ) ( BER ) 100dB 80dB PC TDMA 3.6V 50% 3dB ( Li+ ) 800mA PCB GSM IS-136 ASIC DSP ASIC Li+ PROTECTION BOOST SMPS ASIC P-CH S ENABLE BUCK SMPS 2.0V DIGITAL ASIC PA S ( ASIC ( LDO ) 1) LDO1 ENABLE FREQUENCY SYNTHESIZER ENABLE LDO2 RECEIVE RF ( GSM IS-95 ) LDO3 ENABLE TRANSMIT LDO4 STANDBY POWER 1. 8 MAX881 ( DC-DC ( LO ) IC MAX1688 ) ( 2) ( MAX1687/ ( PLL ) 30kHz ) 2V PLL VCO VCO PLL GaAsFET 25MHz/2V VCO VCO VCO 1 GaAs ( ) 4 MOSFET 2 3 PSRR (TCXO/VCTCXO) Q PLL VCO 12.5MHz/V VCO ( VCO ) AMPS 880MHz ±12.5MHz ( VCO PLL 3V 25MHz ( ) 3) PA MAX881 10 MAX GaAs IC (~1mVp-p) PLL PLL LI+ SHDN CHARGE PUMP IN C3 OUT C4 FB P-CH PA POWER SWITCH C1+ C1 C1NEGOUT C2 C L1 450A (MAX) Li+ R1 MAX1687 IN LX1 LX2 5V OUT 2A PEAK BIAS RF IN MAX881R RF TO ANTENNA PA ……