Overview
The PCA9554APW is a remote 8-bit I2C and SMBus I/O expander produced by Texas Instruments. This device is designed to provide general-purpose remote I/O expansion for most microcontroller families via the I2C interface. It operates within a supply voltage range of 2.3 V to 5.5 V, making it versatile for various applications. The PCA9554APW is pin-to-pin and I2C address compatible with the PCF8574A, although software changes may be required due to the enhancements in the PCA9554APW.
Key Specifications
| Parameter | Value | Notes |
|---|---|---|
| Supply Voltage (VCC) | 2.3 V to 5.5 V | |
| Operating Temperature | -40°C to 85°C | |
| Package Type | 16-TSSOP (0.173, 4.40mm Width) | |
| Number of Pins | 16 | |
| Interface | I2C, SMBus | |
| Number of Bits | 8 | |
| Output Type | Latched, open-drain interrupt output | |
| Operating Supply Current | 104 μA (typical) | At VCC = 2.5 V, 3.3 V, or 5 V, TA = 25°C |
| Maximum Current per I/O | 25 mA | |
| Maximum Total Current for All I/Os | 85 mA |
Key Features
- Remote I/O Expansion: Provides 8-bit remote I/O expansion via the I2C interface, allowing for the control of external devices from a central microcontroller.
- Configurable I/Os: I/Os can be configured as either inputs or outputs by writing to the I/O configuration bits. At power-on, the I/Os are configured as inputs with a weak pull-up to VCC.
- Polarity Inversion: The polarity of the Input Port register can be inverted using the Polarity Inversion register.
- Interrupt Capability: Features an open-drain interrupt output that is activated when any input state differs from its corresponding Input Port register state, allowing the device to signal changes to the microcontroller without continuous I2C communication.
- High-Current Drive Capability: Outputs have high-current drive capability, suitable for directly driving LEDs.
- I2C Addressing: Three hardware pins (A0, A1, and A2) allow for programming and varying the fixed I2C address, enabling up to eight devices to share the same I2C bus or SMBus.
Applications
- Microcontroller Systems: Ideal for expanding the I/O capabilities of microcontrollers in various embedded systems.
- Industrial Automation: Used in industrial automation to control and monitor external devices.
- Consumer Electronics: Suitable for use in consumer electronics where additional I/O ports are needed.
- Automotive Systems: Can be used in automotive systems for controlling and monitoring various functions.
- IoT Devices: Useful in Internet of Things (IoT) devices to expand I/O capabilities and manage external peripherals.
Q & A
- What is the PCA9554APW used for?
The PCA9554APW is used for remote 8-bit I2C and SMBus I/O expansion, providing additional I/O ports for microcontrollers.
- What is the operating voltage range of the PCA9554APW?
The PCA9554APW operates within a supply voltage range of 2.3 V to 5.5 V.
- How many I/O bits does the PCA9554APW provide?
The PCA9554APW provides 8 bits of I/O expansion.
- Can the I/Os of the PCA9554APW be configured as inputs or outputs?
Yes, the I/Os can be configured as either inputs or outputs by writing to the I/O configuration bits.
- What is the purpose of the interrupt output on the PCA9554APW?
The interrupt output is used to signal changes in the input states to the microcontroller without continuous I2C communication.
- How many devices of the PCA9554APW can be connected to the same I2C bus?
Up to eight devices can be connected to the same I2C bus or SMBus by using the three hardware pins (A0, A1, and A2) to vary the fixed I2C address.
- What is the maximum current per I/O and total current for all I/Os?
The maximum current per I/O is 25 mA, and the total current for all I/Os must be limited to 85 mA.
- What is the package type of the PCA9554APW?
The PCA9554APW comes in a 16-TSSOP package.
- Is the PCA9554APW compatible with other Texas Instruments devices?
Yes, it is pin-to-pin and I2C address compatible with the PCF8574A, although software changes may be required.
- What is the operating temperature range of the PCA9554APW?
The operating temperature range is -40°C to 85°C.
