The TPS7510x linear low dropout (LDO) matching LED current source is optimized for low-power keypad and navigation pad LED backlighting applications. The device provides a constant current to up to four unmatched LEDs organized in two banks of two LEDs each in a common-cathode topology. Without an external resistor, the current source defaults to a factory-programmable, preset current level with ±0.5% accuracy (typical). An optional external resistor can be used to set initial brightness to user-programmable values with higher accuracy. Brightness can be varied from off to full brightness by inputting a pulse width modulation (PWM) signal on each enable pin (ENx, where x indicates LED bank A or B). Each bank has independent enable and brightness control, but current matching is done to all four channels concurrently. The input supply range is ideally suited for single-cell Li-Ion battery supplies and the TPS7510x can provide up to 25 mA per LED.
●No internal switching signals are used, eliminating troublesome electromagnetic interference (EMI). The TPS7510x is offered in an ultra-small, 9-ball, 0.4-mm ball-pitch wafer chip-scale package (WCSP) and a 2.50-mm × 2.50-mm, 10-pin WSON package, yielding a very compact total solution size ideal for mobile handsets and portable backlighting applications. The device is fully specified over TJ = –40°C to +85°C.
● Regulated Output Current with 2% LED-to-LED Matching
● Drives Up to Four LEDs at 25 mA Each in a Common Cathode Topology
● 28-mV Typical Dropout Voltage Extends Usable Supply Range in Li-Ion Battery Applications
● Brightness Control Using PWM Signals
● Two 2-LED Banks With Independent Enable and PWM Brightness Control per Bank
● No Internal Switching Signals—Eliminates EMI
● Default LED Current Eliminates External Components
● Default Values from 3 mA to 10 mA (in 1-mA Increments) Available Using Innovative Factory EEPROM Programming
● Optional External Resistor can be Used for High-Accuracy, User-Programmable Current
● Over current and Over temperature Protection
● Available in Wafer Chip-Scale Package
●or 2.50-mm × 2.50-mm WSON-10
