SC667 7 LED Light Management Unit Automatic Dropout Prevention, Ambient Light Sense Input, PWM Dimming, and 4 LDOs POWER MANAGEMENT Features Description Seven LED backlight sinks with 32 current settings The SC667 is a highly integrated light management unit from 0mA to 25mA that provides programmable current for up to seven LED Up to four LED backlight banks current sinks. Four LED banks are provided to allow set- Lighting effects fade-in/fade-out, breathe, blink, tings for various LED zones or indicators. Four low-noise auto-dim full, and auto-dim partial functions LDOs with programmable outputs ranging from 1.2V to 3.3V ADP (Automatic Dropout Prevention) for backlights and 200mA maximum output current are also included. ALS (Ambient Light Sense) option sets the backlight ADP limits the maximum LED current to a level that ensures brightness according to ambient lighting conditions 2 the LEDs maintain matched currents when the supply I C Bus fast mode and standard mode voltage approaches dropout. This feature produces accept- IRQ (Interrupt request) open-drain output indi- able light output at low supply voltage levels without cates a change of state for the ALS requiring a boost converter or charge pump. Backlight current accuracy 1.5% typical Backlight current matching 0.5% typical 2 Two interfaces are provided for design flexibility. The I C Four programmable 200mA low-noise LDO regulators interface controls the LED on/off functions, assigns the PWM interface (200Hz to 50kHz) with internal digital LEDs to backlight banks, programs the LED currents, pro- low-pass lfi ter grams the lighting eeff cts, enables the LDOs, and sets the Automatic sleep mode with all LEDs off LDO output voltages. The PWM interface reduces the Shutdown current 0.1A typical current setting for LED bank 1 by a factor equal to the duty Ultra-thin package 3 x 3 x 0.6 (mm) cycle of the applied PWM signal. A lfi ter at the PWM input Lead-free and halogen-free converts the pulsed signal to a DC current level, resulting in WEEE and RoHS compliant less switching noise compared to pulsed current methods. Applications The ADI input translates the voltage from an external ALS Cellular phones, smart phones, and PDAs (Ambient Light Sensor) into a digitized code using a sigma- LCD modules delta ADC. This block includes level detection to adjust the Portable media players and digital cameras current setting of bank 1 with two dieff rent programmable Personal navigation devices levels based on the ambient light level. An interrupt output Display/keypad backlighting and LED indicators transitions low to notify the host processor that a level adjustment has been made. Typical Application Circuit V IN V IN SC667 2.9 to 5.5V IN BL1 BL2 C IN GND BL3 BL4 2 VDD I C Data SDA BL5 2 BL6 I C Clock SCL R 1 BL7 Backlight PWM PWM IRQ Flag for ALS Device Enable EN LDO1 LDO1 VLDO4 ADI LDO2 LDO2 LDO3 LDO3 BYP LDO4 LDO4 C BYP C C C C4 1 2 3 Ambient Light Sensor December 9, 2010 2010 Semtech Corporation 1SC667 Pin Configuration Ordering Information Device Package (1)(2) SC667ULTRT MLPQ-UT-20 33 SC667EVB Evaluation Board 20 19 18 17 16 Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. LDO1 1 15 IRQ (2) Lead-free package only. Device is WEEE and RoHS compliant and TOP VIEW halogen-free. 14 SDA VIN 2 GND 3 13 SCL PWM 4 12 ADI T 11 BL1 BL7 5 6 7 8 9 10 MLPQ-UT-20 3x3, 20 LEAD = 35C/W JA Marking Information 667 yyww xxxx yyww = Date Code xxxx = Semtech Lot Number 2 BL6 LDO2 BL5 LDO3 BL4 LDO4 BL3 BYP BL2 EN