PCA9534ADB

Product Overview

Category: Integrated Circuit (IC)

Use: The PCA9534ADB is a 16-bit I2C-bus and SMBus I/O expander optimized for dimming LEDs in applications such as backlight control, keypad illumination, and other similar functions. It provides general-purpose parallel input/output expansion for most microcontroller families via the I2C-bus interface.

Characteristics: - 16-bit remote bidirectional I/O port - Low standby current consumption of 1 µA maximum - Schmitt trigger inputs for noise suppression - Active LOW interrupt output - Internal power-on reset - No glitch on power-up - Supports hot insertion - Low standby current - Noise filter on SCL/SDA inputs - Latched outputs with high-current drive capability for directly driving LEDs - Compatible with most microcontrollers - 400 kHz Fast-mode I2C-bus interface

Package: The PCA9534ADB comes in a small 24-pin SSOP package, which allows for easy integration into various electronic devices.

Essence: The essence of the PCA9534ADB lies in its ability to expand the number of available I/O pins of a microcontroller using the I2C-bus interface. This enables efficient control of multiple LEDs or other devices without requiring additional microcontroller pins.

Packaging/Quantity: The PCA9534ADB is typically sold in reels or tubes containing a quantity of 250 units per package.

Specifications

• Supply Voltage: 2.3 V to 5.5 V
• Input/Output Voltage: 0 V to VDD
• Operating Temperature Range: -40°C to +85°C
• I2C-bus Frequency: Up to 400 kHz
• Maximum Standby Current: 1 µA
• Maximum Output Current: 25 mA per I/O pin

Detailed Pin Configuration

The PCA9534ADB has a total of 24 pins, which are assigned specific functions as follows:

1. SDA - Serial Data Input/Output
2. SCL - Serial Clock Input
3. A0 - Address Select Bit 0
4. A1 - Address Select Bit 1
5. RESET - Active LOW Reset Input 6-21. P0-P15 - Bidirectional I/O Pins
6. INT - Interrupt Output
7. VDD - Supply Voltage
8. GND - Ground

Functional Features

• Bidirectional I/O Expansion: The PCA9534ADB provides 16 bidirectional I/O pins that can be individually configured as inputs or outputs.
• LED Dimming: The device supports LED dimming functionality, making it suitable for applications requiring backlight control or keypad illumination.
• Noise Suppression: Schmitt trigger inputs help suppress noise and ensure reliable operation in noisy environments.
• Interrupt Output: The active LOW interrupt output allows the microcontroller to be notified when an input changes state.
• Power-On Reset: The internal power-on reset ensures proper initialization of the device upon power-up.
• Hot Insertion Support: The PCA9534ADB is designed to support hot insertion, allowing it to be connected or disconnected from the I2C-bus without causing any issues.

Advantages and Disadvantages

Advantages: - Efficient I/O Expansion: The PCA9534ADB enables easy expansion of I/O pins, reducing the need for additional microcontroller resources. - LED Dimming Capability: The device's ability to dim LEDs makes it suitable for various lighting control applications. - Low Standby Current: With a maximum standby current of only 1 µA, the PCA9534ADB helps minimize power consumption in low-power designs. - Noise Suppression: The Schmitt trigger inputs ensure reliable operation in noisy environments.

Disadvantages: - Limited I/O Pins: The PCA9534ADB provides 16 bidirectional I/O pins, which may not be sufficient for applications requiring a large number of I/Os. - Requires I2C-bus Interface: The device relies on the I2C-bus interface for communication, which may require additional hardware and software implementation.

Working Principles

The PCA9534ADB communicates with the microcontroller through the I2C-bus interface. It acts as an I/O expander, allowing the microcontroller to control and monitor the state of the 16 bidirectional I/O pins. The device can be configured as inputs or outputs individually, providing flexibility in various applications.

When used for LED dimming, the PCA9534ADB utilizes its high-current drive capability to directly drive LEDs connected to its output pins. By adjusting the duty cycle of the PWM signal sent from the microcontroller, the brightness of the LEDs can be controlled.

Detailed Application Field Plans

The PCA9534ADB finds application in various fields, including but not limited to: - Backlight control in LCD displays