LM27961 Datasheet | National Semiconductor

Description The LM27961 is a charge-pump-based white-LED driver that is ideal for mobile phone display backlighting. It is intended to drive 4 LEDs for a main phone display backlight and 3 LEDs for a sub-display backlight. Regulated internal current sources deliver excellent current and brightness matching in .. all LEDs. The LED driver current sources are split into two independently controlled groups. The primary group (Group A) can be used to backlight a main phone display with up to 4 LEDs. The low-side current drivers of Group A acmodate mon-anode-type LEDs. The second group (Group B) can backlight a secondary display with up to 3 LEDs. The high-side current drivers of Group B acmodate moncathode-type LEDs. Both Group A and Group B can also drive standard two-terminal LEDs, and provide other general lighting functions (keypad lighting, fun lighting, etc). The brightness of the two LED groups can be adjusted independently with external resistors. The LM27961 works off an extended Li-Ion input voltage range (2.7V to 5.5V). Voltage boost is achieved with a highefficiency 3/2x-gain charge pump. The LM27961 is available in National’s chip-scale 18-bump micro SMD package. Features n Drives 4 Individual mon-Anode LEDs with up to 20m A each for a Main Display Backlight n Drives 3 Individual mon-Cathode LEDs with up to 20m A each for a Sub-Display Backlight n Independent Resistor-Programmable Current Setting n Excellent Current and Brightness Matching n High-Efficiency 3/2x Charge Pump n Extended Li-Ion Input: 2.7V to 5.5V n PWM Brightness Control: 100Hz - 1k Hz n 18-bump Thin Micro SMD Package: (2.1mm x 2.4mm x 0.6mm) Applications n n n n Mobile Phone Display Lighting Mobile Phone Keypad Lighting PDAs General LED Lighting Typical Application Circuit © 2004 National Semiconductor Corporation DS201279 .national. Connection Diagram 18-Bump Thin Micro SMD Package, Large Bump NS Package Number TLA18 .. Pin Description Pin #s C1 D2 A3 A1,...