Overview
The PCA9554ADW, produced by Texas Instruments, is an 8-bit I2C and SMBus I/O expander designed for remote I/O expansion in various microcontroller-based systems. This device operates within a voltage range of 2.3V to 5.5V, making it versatile for different application environments. It features an I2C interface with serial clock (SCL) and serial data (SDA) lines, allowing for communication with the system master. The PCA9554ADW includes configuration, input, output, and polarity inversion registers, enabling flexible control over the I/O pins. At power-on, the I/Os are configured as inputs with a weak pull-up to VCC, but can be reconfigured by the system master as needed.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| VCC Operating Voltage | 2.3 to 5.5 | V |
| Operating Free-Air Temperature | -40 to 85 | °C |
| High-Level Input Voltage (SCL, SDA) | 0.7 × VCC | V |
| Low-Level Input Voltage (SCL, SDA) | 0.3 × VCC | V |
| High-Level Output Current (P7–P0) | -10 | mA |
| Low-Level Output Current (P7–P0) | 25 | mA |
| I2C/SMBus Frequency | 100 kHz / 400 kHz | |
| Package Type | SOIC (16-pin), SSOP (16-pin), VQFN (16-pin) |
Key Features
- 8-Bit I/O Expansion: Provides eight configurable I/O pins that can be set as inputs or outputs by the system master.
- I2C and SMBus Compatibility: Supports both I2C and SMBus protocols with frequencies up to 400 kHz.
- Interrupt Capability: Features an open-drain interrupt output that signals changes in the input state.
- Polarity Inversion: Allows for polarity inversion of the input port register, providing flexibility in signal handling.
- High-Current Drive Capability: Outputs have high-current drive capability, suitable for directly driving LEDs.
- Low Power Consumption: Low current consumption in operating and standby modes.
- Addressing Flexibility: Three hardware pins (A0, A1, A2) allow for programming and varying the fixed I2C address, enabling up to eight devices on the same bus.
Applications
- Microcontroller Systems: Ideal for expanding the I/O capabilities of microcontrollers in various embedded systems.
- Industrial Automation: Suitable for use in industrial automation systems where remote I/O expansion is necessary.
- Consumer Electronics: Can be used in consumer electronics to enhance the I/O capabilities of the main controller.
- Automotive Systems: Applicable in automotive systems for expanding I/O functions while maintaining low power consumption).
Q & A
- What is the operating voltage range of the PCA9554ADW?
The PCA9554ADW operates within a voltage range of 2.3V to 5.5V.
- What are the supported I2C/SMBus frequencies?
The device supports I2C/SMBus frequencies up to 100 kHz and 400 kHz.
- How many I/O pins does the PCA9554ADW provide?
The PCA9554ADW provides eight configurable I/O pins.
- What is the purpose of the interrupt output on the PCA9554ADW?
The interrupt output signals changes in the input state, indicating to the system master that an input state has changed.
- Can the polarity of the input port be inverted?
Yes, the polarity of the input port register can be inverted using the Polarity Inversion register.
- What is the maximum low-level output current of the PCA9554ADW?
The maximum low-level output current is 25 mA.
- How many devices of this type can be connected on the same I2C/SMBus?
Up to eight devices of each type (PCA9554 and PCA9554A) can be connected on the same I2C/SMBus, allowing for a total of 16 devices.
- What are the package types available for the PCA9554ADW?
The PCA9554ADW is available in SOIC (16-pin), SSOP (16-pin), and VQFN (16-pin) packages.
- Is the PCA9554ADW compatible with other Texas Instruments devices?
The PCA9554ADW is pin-to-pin and I2C address compatible with the PCF8574, although software changes may be required due to enhancements.
- What is the operating free-air temperature range of the PCA9554ADW?
The operating free-air temperature range is -40°C to 85°C.
