PCA9538APWJ

Product Overview

Category: Integrated Circuit (IC)

Use: The PCA9538APWJ is a 16-pin CMOS device that belongs to the family of I2C-bus controlled 8-bit I/O expanders. It provides general-purpose remote I/O expansion for most microcontroller families via the I2C interface.

Characteristics: - Low standby current consumption - Schmitt trigger inputs for noise suppression - Open-drain interrupt output - Active LOW reset input - Power-on reset - Noise filter on SCL/SDA inputs - Latched outputs with high-current drive capability for directly driving LEDs - Compatible with most microcontrollers - Wide operating voltage range: 2.3V to 5.5V

Package: TSSOP (Thin Shrink Small Outline Package)

Essence: The PCA9538APWJ is designed to provide additional I/O ports for microcontrollers, allowing them to control more devices without using up all available pins.

Packaging/Quantity: The PCA9538APWJ is typically sold in reels or tubes, with 2500 units per reel/tube.

Specifications

• Supply Voltage Range: 2.3V to 5.5V
• Input Voltage Range: GND to VDD
• Output Voltage Range: GND to VDD
• Maximum Output Current: 25mA per I/O pin
• Maximum Standby Current: 1µA
• Operating Temperature Range: -40°C to +85°C

Pin Configuration

The PCA9538APWJ has a total of 16 pins, which are assigned specific functions as follows:

| Pin Number | Pin Name | Function | |------------|----------|----------| | 1 | A0 | Address Input Bit 0 | | 2 | A1 | Address Input Bit 1 | | 3 | A2 | Address Input Bit 2 | | 4 | RESET | Active LOW Reset Input | | 5 | INT | Open-drain Interrupt Output | | 6-13 | P0-P7 | I/O Port Pins | | 14 | SDA | I2C Serial Data Input/Output | | 15 | SCL | I2C Serial Clock Input | | 16 | VDD | Supply Voltage | | - | GND | Ground |

Functional Features

The PCA9538APWJ offers the following functional features:

1. I2C Interface: The device communicates with the microcontroller via the I2C serial bus, allowing for easy integration into existing systems.

2. Remote I/O Expansion: It provides 8 additional I/O ports that can be controlled by the microcontroller, effectively expanding the number of devices that can be connected and controlled.

3. Interrupt Output: The open-drain interrupt output pin (INT) can be used to signal the microcontroller when a specific event occurs, reducing the need for continuous polling.

4. Reset Functionality: The active LOW reset input (RESET) allows the microcontroller to reset the PCA9538APWJ, restoring all registers to their default values.

5. High-current Drive Capability: The latched outputs of the device have a high-current drive capability, making it suitable for directly driving LEDs or other devices that require higher current levels.

Advantages and Disadvantages

Advantages: - Low standby current consumption helps conserve power in battery-powered applications. - Schmitt trigger inputs provide noise suppression, ensuring reliable operation even in noisy environments. - Wide operating voltage range allows compatibility with various microcontrollers. - Power-on reset ensures proper initialization of the device. - Latched outputs with high-current drive capability simplify LED driving applications.

Disadvantages: - Limited number of I/O ports (8) may not be sufficient for certain applications requiring a larger number of devices to be controlled.

Working Principles

The PCA9538APWJ operates by receiving commands from the microcontroller via the I2C interface. The microcontroller sends specific instructions to set or read the state of the individual I/O pins. The device then responds accordingly, either setting the output pins to the desired logic level or providing the current logic level of the input pins.

The interrupt output pin (INT) can be configured to generate an interrupt signal to the microcontroller when a change in the state of any input pin occurs. This allows the microcontroller to respond promptly to events without continuously polling the device.

Detailed Application Field Plans

The PCA9538APWJ finds applications in various fields, including but not limited to:

1. Industrial Automation: It can be used to expand the number of I/O ports available for controlling sensors, actuators, and other devices in