TCA9535RTWR

Updated: 2026-09-15

Overview

The TCA9535RTWR is a 16-bit I/O expander designed for systems requiring additional GPIO pins without increasing microcontroller complexity. Manufactured in CMOS technology, it operates at voltages from 1.65V to 5.5V, making it suitable for low-power and mixed-voltage applications. Its I2C interface allows daisy-chaining multiple devices, supporting up to 8 units on the same bus. The device includes interrupt output functionality, reducing polling requirements and improving system efficiency. Commonly packaged in a 24-pin WQFN, it is RoHS-compliant and rated for industrial temperature ranges (−40°C to +85°C).

Structure and Working Principle

The TCA9535RTWR consists of 16 bidirectional I/O pins grouped into two 8-bit ports (Port 0 and Port 1). Each pin can be independently configured as an input or output via internal registers accessible through the I2C bus. Inputs include programmable pull-up resistors, while outputs feature high-current drive capability (10 mA per pin). An interrupt output pin signals changes on input pins, enabling event-driven designs. The device integrates power-on reset circuitry to ensure default states at startup, minimizing undefined behavior.

Key Features

Low-voltage operation (1.65V–5.5V) allows seamless integration with modern microcontrollers and legacy 5V systems. The I2C bus supports standard (100 kHz) and fast (400 kHz) modes, with clock stretching for compatibility. Notable features include hardware address pins for bus configuration, Schmitt-trigger inputs for noise immunity, and latch-up performance exceeding 100 mA per JESD78. The interrupt output simplifies real-time monitoring, while the small WQFN package (4 mm × 4 mm) saves board space in compact designs.

Application Areas

Industrial automation systems use the TCA9535RTWR for sensor interfacing, relay control, and panel button scanning. Its robustness against electrical noise makes it suitable for factory environments. In consumer electronics, it expands GPIOs in smart home devices, gaming peripherals, and wearable tech. Embedded developers leverage it for prototyping and space-constrained PCBs, where microcontroller pin count is limited. IoT edge nodes benefit from its low power consumption and interrupt-driven architecture.

Maintenance and Precautions

Avoid exceeding absolute maximum ratings (6V on any pin) to prevent damage. Proper PCB layout practices—such as short I2C traces and decoupling capacitors near VCC—ensure signal integrity. For ESD protection, follow JEDEC JESD22-A114 standards during handling. Long-term reliability is achieved by operating within the specified temperature range and avoiding moisture exposure (MSL-3 rating). Firmware should include I2C bus recovery routines to handle lock-up scenarios.

B2B Procurement Guide

Volume pricing typically applies at 1,000+ units, with lead times ranging from 6–12 weeks depending on distributor stock. Authorized channels like TI Direct or franchised distributors (e.g., Arrow, Avnet) ensure genuine parts. Evaluate alternative part numbers (e.g., PCA9535) for drop-in compatibility if supply chain disruptions occur. For design-ins, request evaluation modules (EVMs) from manufacturers to test functionality before mass production. MOQ requirements vary; some distributors offer sample quantities for prototyping.