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SGM3122
White LED Charge Pump Current Source with PWM Brightness Control
GENERAL DESCRIPTION
The SGM3122 is a charge pump with PWM brightness control for white LED supplies in LCD display backlight applications. The supply voltage ranges from 2.7V to 5.5V, it is ideally suited for all applications powered by a single Li-ion battery cell or three to four NiCd, NiMH, or alkaline battery cells.
The device provides a constant current for each LED, and the initial current value can be set by an external resistor. High efficiency is achieved by utilizing a 1×/1.5× fractional conversion technique in combination with very low dropout current sources.
The SGM3122 is capable of driving up to four channels of LEDs at 30mA per channel from a 2.7V to 5.5V input. Additionally, the current controlled charge pump ensures low input current ripple and EMI. A low external part count (two 0.47µF flying capacitors and two small 1µF capacitors at VIN and VOUT) makes this part ideally suited for small, battery-powered applications.
The SGM3122 is available in a Green TQFN-3×3-16L package, and is rated over the -40°C to +85°C temperature range.
FEATURES
Input Voltage Range: 2.7V to 5.5V Drives up to 4 LEDs at 30mA Each LED Brightness Control Through PWM Control
Signal High Efficiency by Fractional Conversion with 1×
and 1.5× Modes Switching Frequency: 1MHz Regulated Output Current with 0.5% Matching Internal Soft-Start Limits Inrush Current Low Input Ripple and Low EMI Over-Current and Over-Temperature Protected Under-Voltage Lockout with Hysteresis Available in Green TQFN-3×3-16L Package
APPLICATIONS
Cellular Phones Smart Phones Digital Cameras Handheld PCs Camcorders PDAs Keypad Backlight
SG Micro Corp www.sg-micro.com
REV. A. 2
SGM3122
White LED Charge Pump Current Source with PWM Brightness Control
PACKAGE/ORDERING INFORMATION
ORDER NUMBER SGM3122YTQ16G/TR
PACKAGE DESCRIPTION
TQFN-3×3-16L
SPECIFIED TEMPERATURE
RANGE
-40°C to +85°C
PACKAGE OPTION
Tape and Reel, 3000
MARKING INFORMATION
3122TQ
ABSOLUTE MAXIMUM RATINGS
Supply Voltage………………….……………….……-0.3V to 6.0V Voltage at EN1, EN2, VOUT, ISET…………..….……-0.3V to VIN Output Current at VOUT………….…………...……………300mA Storage Temperature Range…………………....-65℃ to +150℃
Maximum Junction Temperature……….…...………………160℃
Operating Temperature Range...…........….……. -40℃ to +85℃ Lead Temperature (Soldering 10 sec) ……………………………………………………….…………260℃ ESD Susceptibility HBM……………………………………...……………………4000V MM………………………………………………………………400V
NOTE: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
CAUTION
This integrated circuit can be damaged by ESD if you don’t pay attention .