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Circuit Description
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2-3
2. Baseband Circuit description of SGH-Z105
1. PM6050
1.1. Power Management
Ten low-dropout regulators designed specifically for GSM applications power the terminal and help ensure optimal
system performance and long battery life. It provides seven LDO support for 2.6V, 2.8V while a self-resetting,
electronically fused switch supplies power to external accessories. Ancillary support functions, such as RTC
module and RTC charger, Clock Buffer, aid in reducing both board area and system complexity.
SBI BUS serial interface provides access to control and configuration registers. This interface gives
full control
of the MSM6200 and enables system designers to maximize both standby and talk times.
Supervisory functions. including a reset generator, an input voltage monitor, and a ADC Conertte 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. Keypad Backlight
The Keypad backlight driver output is at pin 17 (KEYBD_DRV) and is designed to drive parallel connected LEDs
directly. Its output current level is SBI-programmable and meets the performance specified below.
Input parameters are not specified since they are internal.
1.3. TCXO Controller and Buffers
The PM6050 IC includes circuits for controlling the TCXO warm-up and buffering its signal for distribution
throughout the handset. Performance specifications are presented below.
2. Connector
2-1. LCD Connector
LCD is consisted of main LCD(color 262K TFT LCD) and small LCD(color 65K LCD). Chip select signals in the
U302, LCD_CS1- can enable small LCD. W_LED_ON signal enables white LED of main LCD, EN_EN signal
enables EL of small LCD.
"RESET-, TFT_RESET_N" signal initiates the Reset process of the LCD.
8-bit data lines(AD(0)~AD(7)) transfers data and commands to Small LCD through by pass capacitor. 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.
Power signals for LCD are "VDD_LP" and "2.8LV". "SPK+" and "SPK-" from U533 are used for audio speaker.
And "Vibrator" from Q702 enables the motor.
