Charge-pump topology with I²C dimming — 7 outputs at 30 mA or 80 mA
The LM27964SQ-C/NOPB: This is a switched-capacitor (charge pump) regulator, not an inductive boost converter — it uses flying capacitors to generate the output voltage, which means no external inductor and a smaller overall footprint on the board. The switching frequency is 700 kHz, high enough to keep the external capacitors small while staying below the AM radio band. Seven independent outputs each rated for 30 mA typical, with a second current setting of 80 mA per channel. The dual rating lets you drive standard backlight LEDs at the lower current and high-brightness strings at the higher one from the same IC — just set the I²C register. The output voltage range is 2 V to 4 V, which covers most single-LED or two-series-LED backlight configurations in small displays. Dimming is handled through the I²C interface — no external PWM pin needed. The host writes a brightness value over the two-wire bus, and the charge pump adjusts the output current accordingly. This saves a GPIO on the microcontroller and keeps the wiring simple on a cramped display board.
A 2x2 via array under the pad to an inner ground plane keeps the junction temperature in check when running all seven channels at 80 mA. Input supply range is 2.7 V minimum to 5.5 V maximum — compatible with single-cell Li-ion (3.0-4.2 V), 3.3 V regulated rails, or 5 V USB power. The internal switches handle the charge-pump switching, so no external FETs are needed. Operating temperature spans -30°C to 85°C — wide enough for most consumer and industrial backlight applications that live indoors or in a vented enclosure.
The LM27964SQ-C/NOPB is sourced through independent distribution channels. No minimum order quantity restrictions beyond standard distributor terms.