PCA9535DW - 16-Bit 400kHz I/O Expander | Texas Instruments
N.º de pieza: PCA9535DW ✓ ActivoPCA9535DW Descripción general
An I/O expander is an interface IC that translates serial I2C or SMBus commands into parallel control and status signals. Within the hierarchy of semiconductor, interface IC, and I/O expander, the PCA9535DW is used when a controller needs more discrete digital lines than its package provides. Each of its 16 ports can be configured independently for input or output, allowing mixed control, monitoring, and status functions on one bus-connected device.
The verified device data identifies 16 I/O lines, operation from 2.3 V to 5.5 V, a maximum bus frequency of 400 kHz, and standby-current consumption as low as 1 uA maximum. It also includes an open-drain interrupt output and configuration registers. The interrupt feature lets a controller respond to a change on configured inputs without continuously polling the device, although the exact hardware behavior and setup must follow the manufacturer datasheet.
The DW ordering code is associated with a 24-pin SOIC package in the supplied distributor data. Tube packaging is identified for PCA9535DW, while the manufacturer product page remains the authoritative source for ordering, lifecycle, pinout, register behavior, electrical limits, and qualification information. The verified snippets do not provide the full pin-to-pin register map or detailed output-drive specifications, so those values are not inferred here.
Typical uses include microcontroller port expansion, industrial control modules, keypad and switch monitoring, relay or indicator control, sensor-interface control, and small embedded systems where I2C connectivity is preferred over dedicating many parallel pins. Designers should account for the device's supply limits, bus pull-up requirements, address configuration, current limits, and input/output mode registers.
A key design consideration is that a serial expander does not eliminate electrical loading: external loads must remain within the datasheet limits, bus rise and fall times must be controlled, and any open-drain interrupt line needs appropriate pull-up treatment. The PCA9535DW is best suited to low- and moderate-speed control signaling rather than high-current drive or high-speed peripheral expansion.
This product page combines the verified Texas Instruments listing, manufacturer datasheet link, distributor identification, package information, and design-oriented guidance to support component selection and engineering review. Distributor pricing and inventory are not provided as exact current values in the verified data and should therefore be confirmed directly with an authorized distributor before procurement.
Alternativas directas para PCA9535DW — 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 PCA9535DW (mismo factor de forma y huella) — difiere en Interface, Interrupt Output, Package.
PCA9535DBR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
PCA9535DWR
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
TCA9535PWR
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
PCA9539PW/Q900
✅ Sustitución directaConsulte el precio
Ver hoja de datos →PCA9535DW Especificaciones
| Device Type | 16-bit I2C/SMBus I/O expander |
| Number of I/O Lines | 16 |
| Supply Voltage Range | 2.3 V to 5.5 V |
| Interfaz | I2C and SMBus |
| Frecuencia de reloj máxima | 400 kHz |
| Interrupt Output | Open-drain interrupt output |
| Configuration Registers | Yes |
| Port Configuration | 16 individual general-purpose I/O ports |
| Low Standby Current | 1 uA maximum |
| Encapsulado | 24-pin SOIC, 0.295 inch / 7.50 mm width |
| Packaging | Tube |
| Tipo de montaje | Surface mount |
| Temperatura de funcionamiento | -40 C to +85 C |
Guía de configuración de pines de PCA9535DW 24-pin soic, 0.295 inch / 7.50 mm width
Configuración de pines para PCA9535DW (encapsulado 24-pin soic, 0.295 inch / 7.50 mm width). La numeración de pines, las funciones y los diagramas de conexión se definen en la hoja de datos del fabricante. Consúltela para conocer el footprint exacto y las directrices de soldadura.
No hay datos detallados de patillaje disponibles para PCA9535DW.
Consulte la hoja de datos para ver la configuración completa de patillas.
Aplicaciones típicas
PCA9535DW es adecuado para 6 aplicacións: Microcontroller GPIO Expansion, Industrial Control Module, Keypad and Switch Monitoring, Relay and Indicator Control, Sensor Interface Control, Small Embedded System Power Sequencing.
Microcontroller GPIO Expansion
The PCA9535DW fits designs where a host controller has fewer GPIO pins than the external system requires. Its 16 configurable ports add digital control and monitoring capacity while retaining a 2.3 V to 5.5 V supply range and a 400 kHz I2C/SMBus interface. In a typical design, the host connects through SCL and SDA, configures port direction and polarity, and uses the interrupt output to react to a change without continuous polling. The benefit is reduced MCU package size and simpler firmware organization; the tradeoff is that every external signal must remain within the device’s verified logic and current limits.
Recomendado
Industrial Control Module
The PCA9535DW is useful in industrial control modules that combine local status lamps, relay-enable signals, selector inputs, and alarm lines around an embedded controller. Its 16 I/O ports reduce the number of host GPIO connections, while the 2.3 V to 5.5 V operating range supports common industrial logic rails. The interrupt output can notify the controller when an input condition changes, assuming the host configures the relevant registers correctly. Engineers must add appropriate transistor or buffer stages for loads beyond the device’s verified output capability and provide any required flyback protection for inductive loads.
Recomendado
Keypad and Switch Monitoring
A PCA9535DW can monitor switch, keypad, or contact-closure signals when the host lacks enough direct input pins. Sixteen inputs can consolidate multiple front-panel conditions into an I2C-readable status device, and the interrupt capability supports event-driven handling rather than constant polling. The verified 400 kHz interface is suitable for ordinary low-speed control traffic, while the 1 uA maximum standby-current value helps when the system periodically enters a low-power state. Correct handling of debouncing, pull-up or pull-down networks, and input polarity is essential; these application-specific values are not specified in the supplied snippets.
Recomendado
Relay and Indicator Control
The PCA9535DW can provide a compact control interface for relays, status LEDs, buzzers, and other digital signaling loads when each output is within the verified electrical limits. Its 16 ports allow multiple control lines to be grouped on one serial bus, simplifying wiring and reducing host-controller pin count. Because the expander is not a power driver, high-current or inductive loads generally need transistor stages, flyback diodes, or dedicated driver circuitry. The open-drain interrupt output can also provide a hardware notification path, while the 2.3 V to 5.5 V range supports both low-voltage and legacy 5 V control architectures.
Recomendado
Sensor Interface Control
The PCA9535DW can provide digital enable, reset, mode-select, or alarm lines for external sensors and front ends. It is particularly useful when a sensor board includes several parallel discrete controls but the available controller communicates through I2C or SMBus. The expander’s 16 mixed-capability ports reduce wiring complexity, and its interrupt output can signal a change without continuous software polling. Confirm that sensor enable timing, signal polarity, leakage current, and bus voltage levels match the PCA9535DW’s manufacturer specifications before deployment.
Recomendado
Small Embedded System Power Sequencing
A PCA9535DW can act as a programmable control hub in a small embedded system that needs to enable, disable, or monitor several subsystems. The 16 ports allow local sequencing lines to be driven from a host controller rather than consuming dedicated GPIO on a compact microcontroller. The verified 2.3 V to 5.5 V supply range makes it compatible with multiple common logic systems, but sequencing delays, load currents, and reset behavior must be designed around the manufacturer’s electrical limits. The device is a control interface, not a power regulator, so supply sequencing and current capability still belong to the associated power circuitry.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para PCA9535DW — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | PCA9535DBR | PCA9535DWR | TCA9535PWR | PCA9539PW |
|---|---|---|---|---|---|
| Package | 24-pin SOIC | 24-pin SOIC | 24-pin SOIC | 24-pin TSSOP | 24-pin TSSOP |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors |
| I/O Count | 16 | 16 | 16 | 16 | 16 |
| Interface | I2C and SMBus | I2C and SMBus | I2C and SMBus | I2C and SMBus | I2C |
Diferenciadores clave
- Broad 2.3 V to 5.5 V supply range (frente a TCA9535PWR)
- 16-bit I/O expansion with configuration registers (frente a PCA9539PW)
- 400 kHz verified bus operation (frente a PCA9535DBR)
- Open-drain event notification (frente a PCA9539PW)
Notas de diseño
Design the I2C SDA and SCL paths as a bus, not as isolated point-to-point traces. Use the pull-up arrangement required by the host voltage and cable length, keep the 400 kHz rate within the verified device capability, and check rise and fall times with the actual bus capacitance. A common implementation is to place the pull-up resistors near the bus master and provide a physically continuous ground reference. Exact resistor values are not supplied here because they depend on bus voltage, capacitance, and timing requirements.
Validate the PCA9535DW supply against the complete system, including the 2.3 V to 5.5 V operating range and the voltage levels used by SDA, SCL, port inputs, port outputs, and the interrupt line. Do not allow pulled-up bus signals to exceed the device’s verified limits. Place the device’s supply decoupling close to the package and keep return current paths short. The supplied snippets do not specify the required capacitor value or detailed absolute-maximum limits, so those values must come from the official datasheet.
Do not treat the 16 ports as unrestricted power outputs. Configure each port direction correctly, confirm the register map before changing polarity or input/output state, and use transistor or driver stages for relays, high-current LEDs, and inductive loads. The open-drain interrupt output requires an appropriate pull-up and a defined electrical connection. Firmware should also account for input debounce and event acknowledgment so that an interrupt does not repeatedly retrigger.
Use the manufacturer’s 24-pin SOIC land pattern and pin numbering when laying out the PCB. Keep the I2C traces short where practical, route them away from noisy switching nodes, and provide a clear ground return. Verify the package width and pin pitch against the official mechanical drawing rather than relying on a distributor snippet. Because the supplied data confirms a 24-pin SOIC but not every pin assignment, the PCB design should be cross-checked against the manufacturer pinout before release.
Información de cumplimiento
The verified data identifies the Texas Instruments product and distributor listings but does not provide specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals declarations for PCA9535DW.
