SAMSUNG x670 Circuit Description 8

2. Circuit Description

2-1. SGH-X670 RF Circuit Description

2-1-1. RX PART

- ANTENNA SWITCH (F101 Front End Module)

→

Switching Tx, Rx path for GSM900, DCS1800 and PCS1900 by logic controlling.

- ANTENNA SWITCH Control Losic (F101)→Truth Table

VC1 VC2 VC3

Tx Mode (GSM900) H L L

Tx Mode (DCS1800/1900) L H L(H)

Rx Mode (GSM900) L L L

Rx Mode (DCS1800) L L L

Rx Mode (PCS1900) L L H

- TRANSCEIVER (U102)

This chip is fully integrated GSM GPRS tri-band transceiver with transmit baluns(balanced-unbalanced matching devices) ,

loop filters and most of the passive component in it.

And also fully integrated fractional N RF synthesizer with AFC control possibility, RF VCO with integrated supply

regulator. Semi integrated reference oscillator with integrated supply regulator.

RF Receiver front-end amplifies the E-GSM900, DCS1800 and PCS1900 aerial signal, convert the chosen channel

down to a low IF of 100kHz.

In IF section, further amplifies the wanted channel output level to the desired value and rejects DC.

-PAM(PAM101)

The module consists of two separated line-ups, one for low band(LB 850/900) and one for high band(HB,1800/1900) with

input and output matching and internal power detection function and power control loop in GSM mode.

in GSM mode, the internal power control circuit ensures a stable power output, set by the level of V

compensate variations of supply voltage, input power and temperature, with a control range fully compaliant with ETSI

tome mask and power spectrum requirements

in EDGE mode the output power is controlled by the input power. The V

controlling the quiescent current of the final RF-statges of both line-ups.

signal is used to control the efficiency by

REF

stabilsed to

DAC

2-1-2. TX PART

The transmitter is fully differential using a direct up conversion architecture. It consists of a signal side band

power up mixer. Gain is controlled by 6 dB via 3-wire serial bus programing. The fully integrated VCO and power

mixer 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.

2-1

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Circuit Description

2-2. Baseband Circuit description of SGH-X670

2-2-1. PCF50603 (U400)

- Power Management

Eight low-dropout regulators designed specifically for GSM applications power the terminal and help ensure optimal

system performance and long battery life. A programmable boost converter provides support for 1.8V, 3.0V SIMs,

while a self-resetting, electronically fused switch supplies power to external accessories. Ancillary support functions,

such as RTC module and High Voltage Charge pump, Clock generator, aid in reducing both board area and system

complexity.

I2C BUS serial interface provides access to control and configuration registers. This interface gives a microprocessor

full control of the PCF50603 and enables system designers to maximize both standby and talk times.

Supervisory functions. including a reset generator, an input voltage monitor, and a temperature sensor, support reliable

system design. These functions work together to ensure proper system behavior during start-up or i n the event of a

fault condition(low microprocessor voltage, insufficient battery energy, or excessive die temperature).

- Backlight Brightness Modulator

The Backlight Brightness Modulator (BBM) contains a programmable Pulse-width modulator (PWM) and FET to

modulate the intensity of a series of LEDs or to control a DC/DC converter that drives LCD backlight.

This phone (SGH-X670) use PWM control to contrast the backlight brightness.

- Clock Generator

The Clock Generator (CG) generates all clocks for internal and external usage. The 32.768 kHz crystal oscillator

provides an accurate low clock frequency for the PCF50603 and other circuitry.

2-2-2. LCD Connector

LCD is consisted of main LCD(color 65K UFB LCD) and sub LCD(color 65K UFB LCD)

Chip select signals in the U305, LCD_MAIN_CS, LCD_SUB_CS can enable LCD. DIM-EN signal enables white LED of

main LCD. These signal is from U200.

16-bit data lines(LD(0)~LD(15)) transfers data and commands to LCD. Data and commands use "RS" signal. If this signal

is high, Inputs to LCD are commands. If it is low, Inputs to LCD are data. The signal which informs the input or output

state to LCD, is required. But this system is not necessary this signal. So "L_WR" signal is used to write data or

commands to LCD. Power signals for LCD are "VDD_IO_HIGH".

2-2-3. BLUE TOOTH

This system uses Blue Tooth module, UGNZ6XG23A, ALPS. This has signals, "BT_INT"(Interrupt signal), "RXD2"(input

data) and "TXD2"(output data), PCM control signal(DCL[PCMCLK], DO[PCM_IN], DU[PCM_OUT], FSC[PCM_SYNC])

These signals are connected to PCF5213EL1EL1.

2-2

SAMSUNG Proprietary-Contents may change without notice

This Document can not be used without Samsung's authorization