PCA9550D
Compact 2-segment LED drivers with multiple voltage support
Manufacturer： nxp
series introduction
# PCA9550D Product Series Introduction
## 1. Overview
The PCA9550D is a highly versatile and reliable product series belonging to the category of I/O expanders. These devices are designed to address the need for additional input - output (I/O) ports in various electronic systems. In modern electronic designs, microcontrollers and other main processing units often have a limited number of available I/O pins. The PCA9550D series serves as an effective solution to this problem by providing a simple and efficient way to expand the number of I/O ports, enabling designers to connect more external devices such as sensors, actuators, and switches.
## 2. Key Features
### 2.1 I²C Interface
- The PCA9550D utilizes the widely - adopted I²C (Inter - Integrated Circuit) bus interface. This serial communication protocol offers several advantages, including simplicity, low - pin count requirements, and the ability to connect multiple devices on the same bus. With the I²C interface, the PCA9550D can be easily integrated into existing systems that already support this protocol, reducing the complexity of the overall design.
- It operates at standard I²C bus speeds, typically up to 100 kHz in the standard mode and up to 400 kHz in the fast mode. This allows for relatively fast data transfer between the PCA9550D and the host controller, ensuring timely communication with external devices.
### 2.2 8 - Bit I/O Expansion
- Each PCA9550D device provides 8 general - purpose I/O (GPIO) pins. These pins can be individually configured as either input or output, giving designers great flexibility in their applications. For example, some pins can be used to read the status of external sensors (input mode), while others can be used to control the operation of actuators (output mode).
- The I/O pins have a high - impedance input state when configured as inputs, which minimizes the loading effect on the connected external signals. When configured as outputs, they can source or sink a sufficient amount of current to drive common external loads such as LEDs or small relays.
### 2.3 Programmable Output Configuration
- The output pins of the PCA9550D can be programmed to operate in different modes. They can be set to either open - drain or push - pull output configurations. The open - drain output mode is useful when multiple devices need to share a common signal line, as it allows for wired - AND connections. The push - pull output mode, on the other hand, provides a strong drive capability and is suitable for directly driving loads that require a high - current source or sink.
### 2.4 Power Supply Range
- The PCA9550D is designed to operate over a wide power supply voltage range, typically from 2.5V to 5.5V. This wide range of power supply compatibility makes it suitable for use in a variety of electronic systems, including those powered by batteries or different power sources. It also allows for easy integration with other components that may have different power requirements.
### 2.5 Interrupt Functionality
- The device features an interrupt output pin. This pin can be configured to generate an interrupt signal to the host controller when there is a change in the state of any of the input pins. This interrupt functionality is extremely useful in applications where real - time monitoring of external events is required. It allows the host controller to respond immediately to changes in the input signals without having to continuously poll the PCA9550D, thereby reducing the processing overhead on the host.
## 3. Applications
### 3.1 Consumer Electronics
- In smart home devices, the PCA9550D can be used to expand the I/O ports of a microcontroller. For
Images for reference
8-SOIC SOT96-1
8-SOIC
8-MSOP