The PCA9551D,118 is a 8-bit I²C-bus LED Driver with programmable blink rates. The LED blinker blinks LEDs in I²C-bus and SMBus applications where it is necessary to limit bus traffic or free up the I²C-bus masters (MCU, MPU, DSP, chip set) timer. The uniqueness of this device is the internal oscillator with two programmable blink rates. To blink LEDs using normal I/O expanders like the PCF8574 or PCA9554, the bus master must send repeated commands to turn the LED on and off. This greatly increases the amount of traffic on the I²C-bus and uses up one of the masters timers. The PCA9551 LED blinker instead requires only the initial set-up command to program blink rate 1 and blink rate 2 (i.e., the frequency and duty cycle) for each individual output. From then on, only one command from the bus master is required to turn each individual open-drain output on, off or to cycle at blink rate 1 or blink rate 2.
● 8 LED drivers (ON, OFF, flashing at a programmable rate)
● Input/outputs not used as LED drivers can be used as regular GPIOs
● Internal oscillator requires no external components
● I²C-bus Interface logic compatible with SMBus
● Internal power-ON reset
● Noise filter on SCL/SDA input
● Active low reset input
● 8 Open-drain outputs directly drive LEDs to 25mA
● Edge rate control on outputs
● No glitch on power-up
● Supports hot insertion
● Low standby current consumption
● Latch-up testing is done to JEDEC standard JESD78 which exceeds 100mA
● 0Hz to 400kHz Clock frequency
