TCA9539

The TCA9539 is a 16-bit I²C-bus and SMBus-compatible port expander designed for low-power applications. It features two 8-bit configurable GPIO ports, each with independent direction control, allowing flexible configuration of input or output modes per pin. The device supports standard-mode (100 kbit/s), fast-mode (400 kbit/s), and fast-mode plus (1 MHz) I²C operation, making it suitable for a wide range of system communication speeds. Each GPIO pin can be individually programmed as an input or output, and the outputs are configured as push-pull drivers with active-high or active-low logic levels. The inputs include programmable internal pull-up resistors, enabling efficient use of board space by eliminating external components. Additionally, the TCA9539 includes interrupt functionality through an open-drain interrupt output (INT), which signals changes in input state, reducing microcontroller polling overhead and improving system efficiency. Designed for low quiescent current consumption—typically 1 μA in standby mode—the TCA9539 is ideal for battery-powered and portable devices where power efficiency is critical. Its wide supply voltage range from 1.65 V to 5.5 V allows compatibility with various logic families and power domains in modern electronic systems. The device operates under standard I²C/SMBus protocols, supporting multiple slave addresses via address pins (A0–A2), enabling up to eight TCA9539 devices on a single bus. This feature simplifies expansion in complex systems requiring additional I/O lines without increasing bus traffic or complexity. Applications include consumer electronics, industrial control systems, automotive infotainment, and IoT devices where additional digital I/O is required but microcontroller pins are limited. Common uses involve controlling LEDs, reading switches, interfacing with sensors, and managing peripheral devices through minimal software intervention. The TCA9539 also includes hardware reset capability via the RESET pin, ensuring reliable initialization in noisy environments or during power-up sequences. Its robust design supports ESD protection and operates reliably across a temperature range from -40°C to +85°C, making it suitable for both commercial and industrial environments.