Overview
The PCA9551D,112 is an 8-bit I2C-bus LED driver with programmable blink rates, manufactured by NXP USA Inc. This device is designed to control LEDs in I2C-bus and SMBus applications, particularly where minimizing bus traffic and freeing up the I2C-bus master's timer are crucial. The PCA9551 features an internal oscillator that allows for two fully programmable blink rates, reducing the need for repeated commands from the bus master and thus lowering the overall bus traffic.
Key Specifications
| Parameter | Value |
|---|---|
| Package Type | SO16 |
| Operating Power Supply Voltage | 2.3 V to 5.5 V |
| Maximum Output Sink Current per Bit | 25 mA |
| Maximum Output Sink Current per Package | 100 mA |
| Blink Rate Frequency Range | 0.148 Hz to 38 Hz |
| I2C-bus Clock Frequency | 0 Hz to 400 kHz |
| ESD Protection | 2000 V HBM, 150 V MM, 1000 V CDM |
| Address Pins | 3 (allowing 8 devices on the same bus) |
| Reset Pin | Active LOW hardware reset |
Key Features
- 8 LED drivers with programmable on, off, and flashing states
- 2 selectable, fully programmable blink rates (frequency and duty cycle)
- Internal oscillator requiring no external components
- I2C-bus interface logic compatible with SMBus
- Internal power-on reset and noise filter on SCL/SDA inputs
- Active LOW reset input and 8 open-drain outputs directly driving LEDs up to 25 mA
- Edge rate control on outputs and support for hot insertion
- Low standby current and no glitch on power-up
Applications
The PCA9551D,112 is suitable for various applications, including LED backlight drivers for LCD displays in tablets and notebooks, refrigeration lighting, and other scenarios where controlled LED blinking is necessary. It is particularly useful in systems where minimizing I2C-bus traffic and conserving the master's resources are important.
Q & A
- What is the primary function of the PCA9551D,112?
The PCA9551D,112 is an 8-bit I2C-bus LED driver with programmable blink rates, designed to control LEDs while minimizing I2C-bus traffic. - What is the range of the programmable blink rates?
The blink rates are programmable between 0.148 Hz and 38 Hz. - What is the maximum output sink current per bit and per package?
The maximum output sink current is 25 mA per bit and 100 mA per package. - What is the operating power supply voltage range?
The operating power supply voltage range is from 2.3 V to 5.5 V. - Does the PCA9551D,112 support hot insertion?
Yes, it supports hot insertion. - How many devices can operate on the same bus using the PCA9551D,112?
Up to 8 devices can operate on the same bus due to the 3 address pins. - What is the purpose of the internal oscillator?
The internal oscillator allows for programmable blink rates without requiring external components. - Does the PCA9551D,112 have ESD protection?
Yes, it has ESD protection exceeding 2000 V HBM, 150 V MM, and 1000 V CDM. - Can unused bits be used for other purposes?
Yes, any bits not used for controlling LEDs can be used as General Purpose parallel Input/Output (GPIO) expansion. - What happens during a power-on reset?
The registers are initialized to their default state, all zeroes, causing the bits to be set HIGH (LED off).
