PCA9551PW,112

The PCA9551PW,112 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 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

Applications

LED Lighting