TCA9535DBT - 16-Bit I/O Expander | Texas Instruments
N.º de pieza: TCA9535DBT ✓ ActivoTCA9535DBT Descripción general
An I/O expander is an interface IC that increases the number of digital input and output pins available to a host controller without requiring a larger microcontroller package. The TCA9535 belongs to the I/O expander hierarchy, where a serial I2C or SMBus connection controls parallel digital lines. Its 16 ports can operate as inputs, outputs, or mixed configurations, making it useful for control panels, sensor aggregation, relay interfaces, and compact embedded systems.
The main features include a wide 1.65 V to 5.5 V operating range, 16 general-purpose I/O lines, separate configuration registers, and an interrupt output. The I2C interface supports operation up to 400 kHz, while the three address inputs allow multiple devices to share the same serial bus. The interrupt output lets the connected processor respond only when a programmed input or output event occurs instead of polling every port continuously.
Internally, the TCA9535 separates the 16 I/O lines into four eight-bit ports. Each port has its own configuration register, while dedicated input and output registers provide independent control of direction and data. This organization supports mixed input and output operation without requiring a separate GPIO controller for every line. Three hardware address inputs select the device address used on the shared bus.
Typical applications include expanding a microcontroller's available GPIO, reading discrete switches and sensors, driving LEDs or digital control signals, implementing a keypad interface, and controlling multiple peripheral enables. The low-voltage operation also suits battery-powered and portable equipment where the host and expander operate from a 1.8 V, 2.5 V, 3.3 V, or 5 V system rail.
Design the bus carefully when several expanders share SDA and SCL. Keep pull-up resistors within the range specified by the manufacturer datasheet, route the bus away from noisy switching nodes, and account for capacitance when increasing cable length or the number of devices. Decoupling close to VCC and GND improves stability in compact systems.
This product page combines the manufacturer's core electrical characteristics, package and pin information, compatibility-focused alternatives, application guidance, and practical design considerations to support faster component selection and PCB planning.
Alternativas directas para TCA9535DBT — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con TCA9535DBT (mismo factor de forma y huella) — difiere en Configuration Registers, Interrupt Output, Number of Ports, Package.
TCA9535DBR
✅ Sustitución directaConsulte el precio
Ver hoja de datos →TCA9535PWR
✅ Sustitución directaConsulte el precio
Ver hoja de datos →PCA9535CD,112
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
TCA9535DBT Especificaciones
| Device Type | 16-bit I2C/SMBus low-power I/O expander |
| Number of I/O Lines | 16 lines |
| Operating Supply Voltage Range | 1.65 V to 5.5 V |
| Maximum I2C/SMBus Clock Frequency | 400 kHz |
| Number of Ports | 4 eight-bit ports |
| Interrupt Output | Yes |
| Configuration Registers | Yes |
| Hardware Address Inputs | 3 |
| Serial Interface | I2C and SMBus |
| Recuento de pines | 24 pins |
| Encapsulado | 24-pin SSOP |
| Rango de temperatura de funcionamiento | -40 °C to +85 °C |
| Tipo de montaje | Surface mount |
| I/O Direction Control | Independent input or output configuration |
Configuración de pines de TCA9535DBT
| Pin 1 | P00 — Port 0 input/output 0 |
| Pin 2 | P01 — Port 0 input/output 1 |
| Pin 3 | P02 — Port 0 input/output 2 |
| Pin 4 | P03 — Port 0 input/output 3 |
| Pin 5 | P04 — Port 0 input/output 4 |
| Pin 6 | P05 — Port 0 input/output 5 |
| Pin 7 | P06 — Port 0 input/output 6 |
| Pin 8 | P07 — Port 0 input/output 7 |
| Pin 9 | P10 — Port 1 input/output 0 |
| Pin 10 | P11 — Port 1 input/output 1 |
| Pin 11 | P12 — Port 1 input/output 2 |
| Pin 12 | P13 — Port 1 input/output 3 |
| Pin 13 | P14 — Port 1 input/output 4 |
| Pin 14 | P15 — Port 1 input/output 5 |
| Pin 15 | P16 — Port 1 input/output 6 |
| Pin 16 | P17 — Port 1 input/output 7 |
| Pin 17 | A0 — Hardware address input 0 |
| Pin 18 | A1 — Hardware address input 1 |
| Pin 19 | A2 — Hardware address input 2 |
| Pin 20 | GND — Ground reference |
| Pin 21 | SCL — Serial clock input |
| Pin 22 | SDA — Serial data input/output |
| Pin 23 | INT — Interrupt output |
| Pin 24 | VCC — Power supply input |
Aplicaciones típicas
TCA9535DBT es adecuado para 6 aplicacións: Industrial Control Panel Interface, LED and Human-Machine Interface Control, Portable Sensor and Switch Aggregation, Programmable Relay and Actuator Interface, Communication and Network Equipment Status Control, Test and Measurement Front Panel.
Industrial Control Panel Interface
The TCA9535DBT suits industrial control panels where a host controller must read switches and command multiple indicators through a limited GPIO budget. Its 16 I/O lines are arranged as four eight-bit ports, allowing inputs and outputs to be mixed while the 1.65 V to 5.5 V operating range supports both legacy 5 V control electronics and lower-voltage embedded systems. Place the expander near the field wiring, use the interrupt output to notify the controller of a changed input, and keep the 400 kHz I2C bus away from relay and power-converter switching nodes.
Recomendado
LED and Human-Machine Interface Control
The TCA9535DBT can reduce the direct I/O burden of a display or keypad subsystem by driving LEDs and reading discrete controls through a serial interface. Sixteen configurable lines provide more than the usual eight lines available from a small controller, while the interrupt output permits event-driven keypad or status detection. Use one port group for outputs and another for switch inputs where practical, configure each line through the port registers, and validate output timing against the indicator load and the host firmware update interval.
Recomendado
Portable Sensor and Switch Aggregation
The TCA9535DBT is appropriate for portable systems that must gather several digital sensor, switch, or enclosure signals without enlarging the host processor package. Its supply range of 1.65 V to 5.5 V permits operation from low-voltage portable rails, and the 16 lines can monitor multiple discrete conditions while controlling a few outputs. For battery-operated equipment, account for the device's quiescent and standby current from the datasheet, use the interrupt output instead of continuous polling, and place local decoupling close to the supply and ground pins.
Recomendado
Programmable Relay and Actuator Interface
The TCA9535DBT can provide a compact command interface for relays, latches, and other digital actuators in industrial or building-control equipment. Sixteen outputs allow multiple channels to be grouped, while the 400 kHz serial interface updates them efficiently from a host processor. Because relay drivers and solenoids create large transients, keep the expander and its traces separated from inductive switching paths, provide local supply filtering, and use appropriate external drive transistors rather than driving unsuitable loads directly from the I/O pins.
Recomendado
Communication and Network Equipment Status Control
The TCA9535DBT is useful in communication equipment for collecting equipment-status inputs and controlling local enable or alarm lines through a shared I2C bus. Three hardware address inputs permit several expanders to coexist when address assignments are carefully planned, while the interrupt output allows the system processor to service only relevant events. Follow the manufacturer's pull-up recommendations for SDA and SCL, isolate the serial bus from high-energy switching circuitry, and confirm that every device on the bus supports the intended operating frequency.
Recomendado
Test and Measurement Front Panel
The TCA9535DBT can expand a compact test instrument's front-panel controls by reading buttons, selectors, and remote-control inputs while driving indicator signals. The four port groups support different input and output assignments, and the interrupt output helps the instrument processor react promptly to operator actions. Keep sensitive analog measurement circuitry away from the digital expander and its routed outputs, use a clean supply connection, and apply the recommended bus pull-ups and decoupling to prevent control activity from disturbing the measurement system.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para TCA9535DBT — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | TCA9535DBR | TCA9535PWR | PCA9535CD,112 |
|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors |
| Package | SSOP-24 | SSOP-24 - same | SSOP-24 - same | SSOP-24 - same |
| Number of I/O Lines | 16 lines | 16 lines | 16 lines | 16 lines |
| Supply Voltage Range | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V | 1.65 V to 5.5 V |
| Interrupt Output | Yes | Yes | Yes | Yes |
| Configuration Registers | Yes | Yes | Yes | Yes |
Diferenciadores clave
- Matches the same 16-channel interface architecture across the closest family choices (frente a TCA9535DBR)
- Provides 16 configurable lines with a 1.65 V minimum supply (frente a PCA9535CD,112)
- Supports event-driven host-controller operation (frente a TCA9535PWR)
Notas de diseño
Route SDA and SCL as a compact, continuous bus and place the pull-up resistors where they can provide the shortest effective connection to the devices on that bus. Keep the TCA9535DBT away from relay drivers, DC-DC converter inductors, and long unprotected field-wiring paths. Preserve a continuous ground reference beneath the device and place the manufacturer-recommended supply capacitor close to VCC and GND to limit transient coupling into the digital ports.
Do not assume that every I/O expander with 16 lines is software-compatible. Program the input, output, polarity, and interrupt registers according to the TCA9535 register map, and verify the behavior of the PCA9535CD,112 against the TCA9535 before changing manufacturers. Also check the package land pattern, address pins, initialization sequence, and interrupt polarity. A functional I/O count match alone is insufficient to establish a safe production replacement.
Calculate the total current drawn from the 1.65 V to 5.5 V supply before assigning the 16 ports, especially when several outputs drive LEDs or external logic. Use the manufacturer's output-current limits rather than assuming all lines can source or sink maximum current simultaneously. Add local decoupling and use separate filtering paths for inductive or noisy loads so switching transients do not pass directly through the expander's supply pins.
Configure unused pins explicitly according to the manufacturer datasheet instead of leaving their state dependent only on power-up defaults. Review the port-direction and output-register initialization order in firmware, because an unintended transient output can activate external hardware. When using the interrupt line, also plan how the host detects and clears each event; otherwise repeated or missed interrupts can make the system appear unreliable.
Información de cumplimiento
The manufacturer product and distributor information does not explicitly state the requested compliance fields for this ordering option. Verify current material and environmental declarations with Texas Instruments before production release.