8-channel I2C LED driver with built-in power switch
The NXP PCA9634D,118 is an 8-output LED driver with integrated power switches, controlled via the I²C bus. Each channel delivers up to 25 mA, and the internal switches eliminate the need for external driver transistors in backlight or indicator arrays.
I2C dimming and channel current matching
Dimming is handled over the I²C interface, with a 25 MHz bus clock ceiling that allows fast register updates for PWM-like brightness control across all eight channels. The integrated switch per output means the driver sinks the LED current directly, so channel-to-channel matching depends on the internal current source tolerance. At 25 mA per channel, the total package dissipation stays manageable in the 20-SOIC body. For layouts sensitive to thermal coupling, the wide 7.50 mm body spreads heat across the copper pours more evenly than narrow SOIC variants.
Package, footprint, and supply routing
Housed in a 20-SOIC (0.295", 7.50 mm width) package, the PCA9634D,118 mounts on standard surface-mount pads. The supply decoupling should sit close to pins 19 (VDD) and 10 (VSS) to keep the I²C bus edges clean; a 0.1 µF ceramic per supply pin is typical.