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.
| Type number | North American Type number | Ordering code (12NC) | Product status | Package | Packing | Marking | Chemical content | Leadfree conversion date |
|---|---|---|---|---|---|---|---|---|
| PCA9550D | PCA9550D | 9352 728 82112 | Volume production | SOT96-1
(SO8) | Tube | Standard Marking | PCA9550D
| week 5, 2005 |
| PCA9550D | PCA9550D-T | 9352 728 82118 | Volume production | SOT96-1
(SO8) | Tape reel smd | Standard Marking | PCA9550D
| week 5, 2005 |
| PCA9550DP | PCA9550DP-T | 9352 728 81118 | Volume production | SOT505-1
(TSSOP8) | Reel Pack, SMD, 13" | Standard Marking | PCA9550DP
| week 12, 2005 |
| PCA9550TK | 9352 856 67118 | Development | SOT908 | Reel Pack, SMD, 13" | Standard Marking | Not available
|
| Type number | Ordering code(12NC) | Indicative price/unit($) | Region | Distributor | In stock | Order quantity | Inventory date | Buy online | Samples |
|---|---|---|---|---|---|---|---|---|---|
| PCA9550D | 9352 728 82112 | 0.9600 | NA | AVNET ELECTRONICS MARKETING | 407 | 1/7/2009 | Buy online | not available | |
| NA | DIGI-KEY CORPORATION | 1,931 | 1/6/2009 | Buy online | |||||
| PCA9550D | 9352 728 82118 | 0.9600 | NA | MOUSER ELECTRONICS | 191 | 1/7/2009 | Buy online | Order samples | |
| PCA9550DP | 9352 728 81118 | 0.9600 | NA | DIGI-KEY CORPORATION | 2,500 | 1/6/2009 | Buy online | Order samples | |
| NA | DIGI-KEY CORPORATION | 2,918 | 1/6/2009 | Buy online | |||||
| PCA9550TK | 9352 856 67118 | not available |
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Application Notes
Support Documents
| Type number | Package | Operating temp.(Cel) | PWMs | # of Bits | I²C-bus(kHz) | Operating voltage(VDC) | Max Sink Current per bit(mA) | # of Addresses | Max Sink Current per package(mA) | Reset input pin |
|---|---|---|---|---|---|---|---|---|---|---|
| PCA9550D | SOT96-1
(SO8) | -40~85 | 2 (40 Hz to 6.4 sec) | 2 | 400 | 2.3~5.5 | 25 | 2 | 50 | yes |
| PCA9550DP | SOT505-1
(TSSOP8) | -40~85 | 2 (40 Hz to 6.4 sec) | 2 | 400 | 2.3~5.5 | 25 | 2 | 50 | yes |
Similar products
PCA9550
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