8-channel PWM LED driver in 16-SOIC
The PCA9551D,118 is an NXP LED driver IC that integrates eight open-drain power-switch outputs, each capable of sinking 25 mA, with a programmable PWM dimming block on a single 16-SOIC package.
PWM dimming and per-channel current limit
Each of the eight outputs is a power switch with an internal MOSFET — no external driver needed — and the PWM dimming block generates the duty-cycle waveform on-chip, so the host microcontroller only writes the blink rate via the I²C-bus interface. The 25 mA per-channel current rating is the sink capability at the output pin; the actual LED current is set by an external series resistor between the supply and the LED anode, while the driver pulls the cathode to ground. Because the PWM is integrated, the host MCU is free from real-time timing loops — a single I²C write programs the blink phase and duty cycle for all eight channels, and the driver runs autonomously.