The PCA9955ATWJ is an I²C-bus controlled 16-channel constant current LED Driver optimized for dimming and blinking 57mA red/green/blue/amber (RGBA) LEDs in amusement products. Each LED output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller that operates at 31.25kHz with a duty cycle that is adjustable from 0 to 100% to allow the LED to be set to a specific brightness value. An additional 8-bit resolution (256 steps) group PWM controller has both a fixed frequency of 122Hz and an adjustable frequency between 15Hz to once every 16.8 seconds with a duty cycle that is adjustable from 0 to 99.6% that is used to either dim or blink all LEDs with the same value. Each LED output can be off, on (no PWM control), set at its individual PWM controller value or at both individual and group PWM controller values. It operates with a supply voltage range of 3V to 5.5V and the constant current sink LED outputs allow up to 20V for the LED supply.
● Programmable group dimming/blinking mixed with individual LED brightness
● Programmable LED output delay to reduce EMI and surge currents
● Each channel can assign to one of four gradation control groups
● Output current adjusted through an external resistor (REXT input)
● Open/short load/over-temperature detection mode to detect individual LED errors
● Software Reset feature (SWRST Call) allows device to be reset through I²C-bus
● 8MHz Internal oscillator requires no external components
● Internal power-on reset
● Noise filter on SDA/SCL inputs
● No glitch on LED outputs on power-up
● Latch-up testing is done to JEDEC standard JESD78 that exceeds 100mA
●ESD sensitive device, take proper precaution while handling the device.
