LG KE990 Service Manual - Page 22

3. TECHNICAL BRIEF ■ Integrated handset-level housekeeping functions reduces external parts count, size, cost - Analog multiplexer selects from 8 internal and up to 18 external inputs - Multiplexer output's offset and gain are adjusted, increasing the effective ADC resolution - Adjusted multiplexer output is buffered and routed to an ESM device ADC - Dual oscillators - 32.768 kHz off-chip crystal and on-chip RC assures ESM device sleep clock - Crystal oscillator detector and automated switch-over upon lost oscillation - Real time clock for tracking time and generating associated alarms - On-chip adjustments minimize crystal oscillator frequency errors - Circuits control TCXO warm-up and synchronize, deglitch, and buffer the TCXO signal - TCXO buffer control for optimal QPH/catnap timing - Three-stage over-temperature protection (smart thermal control) ■ Integrated handset-level user interfaces - Four programmable current sinks recommended as keypad backlight, LCD backlight, camera flash, and general-purpose drivers - Vibration motor driver programmable from 1.2 to 3.1V in 100 mV increments - Speaker driver with programmable gain, turn-on time, and muting; differential operation (drives external 8 Ω speakers with volume controlled 500 mW) ■ IC-level interfaces - ESM device-compatible 3-line SBI for efficient initialization, status, and control - Supports the ESM device's interrupt processing with an internal interrupt manager - Many functions monitored and reported through real-time and interrupt status signals - Dedicated circuits for controlled power-on sequencing, including the ESM device's reset signal - Several events continuously monitored for triggering power-on/power-off sequences - Supports and orchestrates soft resets - USB-OTG transceiver for full-speed (12 Mb/s) and low speed (1.5 Mb/s) interfacing of the ESM device to computers as a USB peripheral, or connecting the ESM device to other peripherals - RUIM level translators enable ESM device interfacing with external modules ■ Twelve multi-purpose pins that can be configured as digital or analog I/Os, bidirectional I/Os, or current sinks. Default functions support the RUIM level translators, power-on circuits, analog multiplexer inputs, an LED driver, and a reference voltage buffer. ■ Highly integrated functionality in a small package - 84-pin BCCS with a large center slug for electrical ground, mechanical stability, and thermal relief Copyright © 2008 LG Electronics. Inc. All right reserved. Only for training and service purposes - 23 - LGE Internal Use Only