TCA9535

The TCA9535 is a 16-bit I²C-bus and SMBus-compatible GPIO expander designed for low-power applications. It features two 8-bit configurable ports (Port 0 and Port 1), each capable of being independently set as input or output, enabling flexible control over external devices. The device supports standard I²C speeds up to 400 kHz and fast-mode speeds up to 1 MHz, ensuring efficient communication with microcontrollers or processors. Each pin can be individually configured for open-drain or push-pull output modes, providing adaptability in various circuit designs. One of the key features of the TCA9535 is its low quiescent current consumption—typically less than 1 µA in standby mode—which makes it ideal for battery-powered systems requiring extended operational life. It also includes configurable polarity inversion for each port, allowing the logic level of input pins to be inverted without software intervention. This simplifies design integration when interfacing with active-low sensors or switches. Additionally, the device supports interrupt-driven operations via an open-drain INT pin that asserts when any input pin changes state, reducing CPU load in embedded systems. The TCA9535 operates from a supply voltage range of 1.65 V to 5.5 V, making it compatible with both 3.3 V and 5 V logic families. Its wide operating voltage range ensures flexibility across diverse power domains in modern electronic systems. The device incorporates internal pull-up resistors for input pins, which can be disabled to reduce power consumption when not needed. Furthermore, it includes built-in protection against electrostatic discharge (ESD) and over-voltage conditions, enhancing reliability in industrial and consumer environments. This GPIO expander is commonly used in applications such as smart home devices, IoT gateways, industrial control panels, and portable electronics where additional I/O lines are required but space or pin count on the main controller is limited. It is especially suited for scenarios involving sensor arrays, LED drivers, relay controls, and user interface elements like buttons and switches. The TCA9535’s compatibility with both I²C and SMBus protocols allows seamless integration into existing system architectures without requiring significant hardware or firmware modifications. Due to its compact 24-pin VQFN package and robust performance characteristics, the TCA9535 offers a reliable and scalable solution for expanding digital I/O capabilities in resource-constrained systems. Its combination of low power, high flexibility, and ease of use makes it a preferred choice for engineers designing efficient, modern electronic products.