PCA9551

General description

The PCA9551 LED blinker blinks LEDs in I²C-bus and SMBus applications where it is necessary to limit bus traffic or free up the I²C-bus 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 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. Maximum output sink current is 25 mA per bit and 100 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).

Three hardware address pins on the PCA9551 allow eight devices to operate on the same bus.

Features

• 8 LED drivers (on, off, flashing at a programmable rate)
• 2 selectable, fully programmable blink rates (frequency and duty cycle) between 0.148 Hz and 38 Hz (6.74 seconds and 0.026 seconds)
• 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 inputs
• Active LOW reset input
• 8 open-drain outputs directly drive LEDs to 25 mA
• Edge rate control on outputs
• 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 Hz 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: SO16, TSSOP16, HVQFN16

Products/packages

Pricing/ordering/availability

Applications

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Transceiver board
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Cellular phone - MMS functionality
Set-top box - MMS functionality
Color mixing for RGBA LEDs

Block diagrams/pinning

Technical documents

Application Notes

AN10146_02; I2C 2002-1A Evaluation Board (26-Feb-03)

AN10216_1; I2C manual (27-Mar-03)

AN10441_1; Level shifting techniques in I²C-bus design (20-Jun-07)

AN264; I2C Devices for LED Display Control (22-Jul-02)

Support Documents

75015669; Continuous innovation. Timeless lifespan. (01-Sep-06)

design_con_2003_tecforum_i2c_bus_overview; DesignCon 2003 TecForum I 2 C Bus Overview (2003-01-27)

75015568; Easily test and demo LED dimming and blinking (01-Jun-06)

75013239; I 2 C Logic Selection Guide (2005-01-12)

75011212; I2C 2002-1A Evaluation Board Kit (01-Mar-03)

75009895; I2C Bus Solutions - Industrial/Motor Control Applications: Numeric Control Machine (2002-06-01)

75012744; I2C Bus Solutions 2004 (2004-02-01)

UM10206_1; I2C Demonstration Board 2005-1 Quick Start Guide (13-Jun-06)

philips_i2c_handbook; I2C Handbook (2004-01-01)

i2c_overview_2h_2003; I2C Overview 2H 2003 ()

UM10204_3; I2C-bus specification and user manual (26-Jun-07)

pca9551; IBIS model of PCA9551 8-bit I2C LED driver with programmable blink rates SO 16-pin Package TSSOP 16-pin Package (2002-04-17)

philips_i2c_logic_overview; Interface Products Business Line Specialty Logic Product Line I2C Logic Family Overview (2004-01-01)

75016021; NXP 2/4/8/16-bit I2C/SMBus LED blinkers PCA9550/51/52/53 (2007-06-01)

75016073; NXP 2/4/8/16-bit I2C/SMBus LED dimmers PCA9530/31/32/33 (2007-06-01)

75016022; NXP 8/16-bit I2C/SMBus GPIO expanders PCA9554/54A/55 (2007-06-01)

75010198; PCA9530/9533/9531/9532 LED Dimmers (25-Sep-02)

75010654; PCA9550/9551/9552 (01-Dec-01)

75015353; PCA9633 - Better control of RGBA LEDs (01-Feb-06)

75014395; Your connection to I 2 C,UART,CAN,and USB Connecting with Philips Wired Connectivity (2005-04-01)

Parametrics/similar products

Similar products

PCA9551 links to the similar products page containing an overview of products that are similar in function or related to the type number(s) as listed on this page. The similar products page includes products from the same catalog tree(s), relevant selection guides and products from the same functional category.

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