Charge-pump LED driver with I²C dimming
The Texas Instruments LM2756TM/NOPB is a switched-capacitor charge-pump regulator designed to drive up to eight LEDs at 30 mA per channel for backlight applications. It uses an I²C interface for dimming control, which saves GPIO pins on the host controller compared to PWM-dedicated lines. The internal switches eliminate the need for external inductors, keeping the BOM compact for space-constrained displays.
Input range and switching frequency
The supply range spans 2.7 V to 5.5 V, covering single-cell Li-ion and 3.3 V or 5 V regulated rails. The charge pump runs at 1.3 MHz, which keeps switching noise above the audio band and allows small external capacitors. At 1.3 MHz the ripple is easier to filter than a lower-frequency part, but the layout still needs tight loop routing to the flying capacitors.
Package and mounting
Housed in a 20-bump DSBGA (0.4 mm pitch typical), this is a wafer-level chip-scale package with no leads. Rework requires a hot-air station with a fine nozzle, preheat from the bottom, and careful alignment — the bumps are hidden once placed. The orientation mark is a small dot on the top surface; verify it under magnification before placement. A stencil with 0.3 mm aperture and 0.4 mm pitch works for solder paste.
Temperature grade and environment
Rated for -30°C to 85°C ambient, this part suits indoor consumer and commercial equipment — display backlighting in tablets, point-of-sale terminals, instrumentation panels, and similar. It is not specified for automotive or extended industrial beyond 85°C.
Lifecycle and sourcing
The LM2756TM/NOPB carries an Active product status and is ROHS3 compliant per the manufacturer.