Overview
The PCA9557PW, produced by Texas Instruments, is an 8-bit I2C and SMBus low-power I/O expander. This device is designed to provide general-purpose remote I/O expansion for most microcontroller families through the I2C interface. It operates within a power-supply voltage range of 2.3V to 5.5V, making it versatile for various applications. The PCA9557PW features low standby current consumption, which is beneficial for power-sensitive designs.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Operating Power-Supply Voltage Range | 2.3V to 5.5V | V |
| Standby Current Consumption | 1 μA (maximum) | μA |
| I2C Bus Frequency | Up to 400 kHz | kHz |
| Number of I/O Bits | 8 | - |
| Input/Output Configuration | Configurable as inputs or outputs | - |
| Polarity Inversion | Input port register polarity can be inverted | - |
| Reset Pin | Requires a pullup resistor to VCC if not actively connected | - |
| Package Types | TSSOP16, among others | - |
Key Features
- Low standby current consumption of 1 μA maximum, making it suitable for power-sensitive applications.
- I2C to parallel port expander, allowing for easy integration with microcontrollers.
- Operating power-supply voltage range of 2.3V to 5.5V, providing flexibility in various system designs.
- Configurable 8-bit input/output ports, enabling the system controller to set the I/Os as either inputs or outputs.
- Polarity inversion capability for the input port register, enhancing flexibility in signal handling.
- Reset pin with internal power-on reset, ensuring the device initializes correctly upon power-up.
Applications
- Telecom shelters and filter units.
- Servers and routers (telecom switching equipment).
- Personal computers and personal electronics.
- Industrial automation systems.
- Products with limited GPIO capabilities, where additional I/O expansion is needed.
Q & A
- What is the PCA9557PW used for?
The PCA9557PW is used as an 8-bit I2C and SMBus low-power I/O expander to provide additional I/O ports for microcontrollers.
- What is the operating voltage range of the PCA9557PW?
The operating voltage range is from 2.3V to 5.5V.
- What is the maximum standby current consumption of the PCA9557PW?
The maximum standby current consumption is 1 μA.
- Can the I/O ports of the PCA9557PW be configured?
Yes, the I/O ports can be configured as either inputs or outputs by the system controller.
- Does the PCA9557PW have a reset feature?
Yes, it has a reset pin and an internal power-on reset feature.
- What are some common applications of the PCA9557PW?
Common applications include telecom shelters, servers, routers, personal computers, personal electronics, and industrial automation systems.
- What is the maximum I2C bus frequency supported by the PCA9557PW?
The maximum I2C bus frequency supported is up to 400 kHz.
- Can the polarity of the input port register be inverted?
Yes, the polarity of the input port register can be inverted using the polarity inversion register.
- What type of packages is the PCA9557PW available in?
The PCA9557PW is available in various packages, including TSSOP16.
- How does the PCA9557PW handle power-on reset?
The device has an internal power-on reset that holds the PCA9557 in a reset condition until VCC reaches the power-on reset threshold (VPOR).
