Circuit Description; General Description; Rf Part - LG KE590 Service Manual

3. Circuit Description

3.1 General Description

The RF part consists of a transmitter, a receiver, a synthesizer, a voltage supply and a DCXO part.
The main RF Chipset B6PLD is a highly integrated RF tranceiver IC FOR Digital Interface of GSM 850,
GSM900, DCS1800 and PCS1900 quad-band cellualr systems. The B6PLD incorporates EDGE
tranceiver apability, quad R low-noise amplifiers(LNSa). Direct conversion mixers, a programmable
gain amplifier(PGA) with DC offset and frequency response correction, ADC, Digital filiter, Digital
Interface, fully integrated VCOs, an RF fractiona-N synthesiser, a low-noise offset PLL transmitter,
Digital modulator, TXDAC, RAMPDAC, and AFCDAC. The B6PLD includes state machine control
through serial programming. All functions operate down to 2.67V and are housed in a 72-pin BGA
package. Hence the B6PLD can form a small size transceiver handset for quad band EDGE
tranceiver.

3.2 RF Part

3.2.1 Receiver Part
The B6PLD receiver supports quad band, so the front-end incorporates four LNAs and two mixers.
The incoming RF signals are mixed directly down to I/Q baseband by the front-end bolck. This
incorporates four LNAs/four buffers and two Gillbert Cell mixer blocks optimised for operation at
850MHz, 900MHz, 1800MHz and 1900MHz respectively. The front-end block is followed by two
closely matched baseband amplifier chains. These include distributed low pass filtering, one switched
gain stage and one fixed gain stage. In addition, the baseband section integrates A/D and D/A
converters which provide automatic on-chip correction of DC offsets.
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
<Fig.1> Receiver Part Block Diagram
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3. Circuit Description
LGE Internal Use Only