Samsung SGH-D500 Circuit Descriptions

2. SGH-D500,SGH-D500E Circuit Description

1. SGH-D500,SGH-D500E RF Circuit Description

1) RX PART

1. ANTENNA SWITCH (U100 SWICHPLEXER)

→

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

2. ANTENNA SWITCH Control Losic (U100)→Truth Table
VC1 VC2 VC3

Tx Mode (GSM900) L H L
Tx Mode (DCS1800/1900) L(H) L H
Rx Mode (GSM900) L L L
Rx Mode (DCS1800) L L L
Rx Mode (PCS1900) H L L

3. FILTER

To convert Electromagnetic Field Wave to Acoustic Wave and then pass the specific frequency band.

- GSM FILTER (F100)→For filtering the frequency band between 925 and 960 MHz

- DCS FILTER (F102)→For filtering the frequency band between 1805 and 1880 MHz.

- PCS FILTER (F101)→For filtering the frequency band between 1930 and 1990 MHz.

4. VC-TCXO (U101)

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 system
through the transceiver pin CLKOUT.

5. TRANSCEIVER (U102)

This chip is fully integrated GSM GPRS quad-band transceiver with transmit baluns, 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.

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.

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Circuit Description

2. Baseband Circuit description of SGH-D500,SGH-D500E

1. PCF50603 (U400)

1.1. 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 in the event of a
fault condition(low microprocessor voltage, insufficient battery energy, or excessive die temperature).

1.2. 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 LED’s or to control a DC/DC converter that drives LCD backlight.
This phone (SGH-D500,SGH-D500E) use PWM control to contrast the backlight brightness.

1.3. 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. LCD Connector
LCD is consisted of main LCD(color 26K TFT LCD).
Chip select signals in the U305, LCD_CS, can enable LCD. BACKLIGHT signal enables white LED of main LCD. These
signal is from U400.
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".

3. IRDA

This system uses IRDA module, HSDL_3209, Agilent's. This has signals, "IRDA_EN"(enable signal), "IRDA_RXD"(input
data) and "IRDA_TXD"(output data). These signals are connected to PCF5213EL1 through BT Module.

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This Document can not be used without Samsung's authorization