Boost LED driver with dual outputs and 25V rail
The Texas Instruments LM3503SQ-25/NOPB is a DC DC Regulator using a Step-Up (Boost) topology, designed primarily for backlight applications. It delivers a regulated 25V output from a 2.5V to 5.5V supply, with two independent outputs each capable of driving separate LED strings. Each output channel supports a 600mA integrated switch, and the part operates at a 1MHz switching frequency, allowing the use of small external inductors and capacitors.
Dimming flexibility and package footprint
The LM3503SQ-25/NOPB supports both Analog and PWM dimming methods, giving the backlight designer control over brightness without trade-offs in colour temperature or flicker. The PWM dimming input accepts a standard logic-level signal, making it straightforward to interface with a microcontroller or timing controller. Housed in a 16-WFQFN Exposed Pad package (4x4mm body, WQFN), the part is surface-mount and requires a thermal pad connection to the PCB ground plane for effective heat dissipation.
New designs should not target this part. No official replacement part is listed by TI on this record.