Overview
●The PCA9550 LED blinker blinks LEDs in I²C-bus and SMBus applications where it is necessary to limit bus traffic or free up the I²C master"s (MCU, MPU, DSP, chip set, etc.) 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 master"s timers. The PCA9550 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). 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. Maximum output sink current is 25 mA per bit and 50 mA per package.
●Any bits not used for controlling the LEDs can be used for General Purpose parallel Input/Output (GPIO) expansion.
●The active LOW hardware reset pin (RESET) and Power-On Reset (POR) initializes the registers to their default state, all zeroes, causing the bits to be set HIGH (LED off).
●One hardware address pin on the PCA9550 allows two devices to operate on the same bus.
●MoreLess
●## Features
● 2 LED drivers (on, off, flashing at a programmable rate)
● 2 selectable, fully programmable blink rates (frequency and duty cycle) between 0.172 Hz and 44 Hz (5.82 seconds and 0.023 second)
● Input/output 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 inputs
● Active LOW reset input
● 2 open-drain outputs directly drive LEDs to 25 mA
● Controlled edge rates to minimize ground bounce
● No glitch on power-up
● Supports hot insertion
● Low standby current
● Operating power supply voltage range of 2.3 V to 5.5 V
● 0 kHz to 400 kHz clock frequency
● ESD protection exceeds 2000 V HBM per JESD22-A114, 150 V MM per JESD22-A115 and 1000 V CDM per JESD22-C101
● Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
● Packages offered: SO8, TSSOP8 (MSOP8), HVSON8
●## Features
