Samsung SGH-E350 Service Manual

Also see for SGH-E350: Service manual Service manual

SAMSUNG Proprietary-Contents may change without notice1. SGH-E350 RF Circuit Description1) RX PART1. FRONT END MODULE(ANTENNA SWITCH MODULE + RX SAW FILTER) (MODULE1)Switching Tx, Rx path for GSM900, DCS1800 and PCS1900 by logic controlling.2. FRONT END MODULE Control Losic (MODULE1) Truth TableVC1 VC2 VC3Tx Mode (GSM900) H L LTx Mode (DCS1800/1900) L H H(L)Rx Mode (GSM900) L L LRx Mode (DCS1800) L L LRx Mode (PCS1900) L L H3. VC-TCXO (U102)This module generates the 26MHz reference clock to drive the logic and RF.It is turned on when the supply voltage +VCC_SYN is applied.After buffering a reference clock of 26MHz is supplied to the other parts of the systemthrough the transceiver pin OUT.4. TRANSCEIVER (U100)This chip is fully integrated GSM GPRS tri-band transceiver with VCO, loop filters and most of thepassive component in it.And also fully integrated fractional N RF synthesizer with AFC control possibility, RF VCO with integrated supplyregulator. Semi integrated reference oscillator with integrated supply regulator.RF Receiver front-end amplifies the E-GSM900, DCS1800 and PCS1900 aerial signal, convert the chosen channeldown to a low IF of 100kHz.In IF section, further amplifies the wanted channel output level to the desired value and rejects DC.2) TX PARTThe transmitter is fully differential using a direct up conversion architecture. It consists of a signal side bandpower up mixer. Gain is controlled by 6 dB via 3-wire serial bus programing. The fully integrated VCO and powermixer achieve LO suppression, quadrature phase error, quadrature amplitude balance and low noise floor specification.Output matching/balun components drive a standard 50 ohms single ended load.