PCA9535PW - 16-Bit I2C GPIO Expander | NXP | TSSOP-24
料号： PCA9535PW ✓ 量产中PCA9535PW 概述
An I2C GPIO expander is an interface IC that translates serial commands from a microcontroller into parallel digital inputs or outputs. Within the hierarchy of interface ICs, an I/O expander sits below general-purpose bus controllers and above application-specific port devices. The PCA9535PW is designed for systems where the host processor has too few direct pins for switches, LEDs, sensors, relays, or control signals.
Key features include 16 configurable GPIO ports, a 400 kHz I2C interface, interrupt output, configuration registers, and low standby-current consumption. According to the verified component listing, standby current is no more than 1 µA. The PCA9535 also supports low-power operation when I/O ports are held low because it removes the internal I/O pull-up resistors used by the related PCA9555.
Technically, the device provides separate input/output and polarity-inversion registers, allowing firmware to reinterpret pins without changing the physical circuit. The PCA9535 is described by NXP as pin-to-pin and I2C-address compatible with the PCF8575, although software changes are required for its enhanced register behavior. It is also described as functionally equivalent to the PCA9555 except for the absence of internal I/O pull-up resistors.
Typical applications include industrial control panels, sensor aggregation, LED and switch interfaces, programmable logic controllers, and embedded systems requiring more GPIO than the host controller provides. The interrupt output can indicate a change on an input port without continuous polling, while the 2.3 V to 5.5 V supply range supports both 3.3 V and 5 V systems.
Designers should account for the absence of internal I/O pull-ups by adding external resistors wherever open-drain, floating, or high-impedance input behavior is required. Pull-ups are also normally installed on the I2C bus itself. The address pins should be checked against the selected bus voltage and system address map before firmware configuration.
This page consolidates the verified manufacturer and distributor information for PCA9535PW, including function, procurement considerations, qualified alternatives, comparison parameters, and practical design guidance that are not presented as one continuous datasheet summary.
直接替换替代料： PCA9535PW ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： PCA9535PW （相同外形与封装尺寸） ——差异在于 Device Type, Package.
PCA9535CPW
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
PCA9555PW
✅ 直接替换联系询价
查看数据手册 →PCA9555PW
✅ 直接替换联系询价
查看数据手册 →PCA9535PWR
✅ 直接替换📋 参考替代料（不在目录中）
PCA9535PW 规格参数
| Device Type | 16-bit I2C/SMBus GPIO expander with interrupt output |
| Number of I/O Ports | 16 ports |
| 接口类型 | I2C and SMBus |
| I2C Maximum Clock Frequency | 400 kHz |
| Operating Supply Voltage Range | 2.3 V to 5.5 V |
| 封装 | 24-TSSOP |
| Package Width | 4.40 mm |
| Package Length | 0.173 in |
| 安装类型 | Surface mount |
| Standby Current | 1 uA maximum |
| Interrupt Output | Yes |
| Configuration Registers | Yes |
| Internal I/O Pull-Up Resistors | Not fitted |
| PCF8575 Compatibility | Pin-to-pin and I2C-address compatible with software changes required |
| Related Device Relationship | Functionally equivalent to PCA9555 except internal I/O pull-up resistors are removed |
| Device Class | CMOS I/O port expander |
| Operating Status | Production |
PCA9535PW 0.173 in 引脚配置指南
PCA9535PW（0.173 in 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： PCA9535PW.
请参阅 数据手册 以查看完整引脚配置。
典型应用
PCA9535PW 适用于 6 应用s: Industrial Control Panel I/O, Sensor Aggregation and Discrete Inputs, LED and Human-Interface Control, Embedded Instrument Control, Programmable Logic Controller I/O, Low-Power Portable Device Interface.
Industrial Control Panel I/O
The PCA9535PW is useful in industrial control panels where a controller must operate switches, status lamps, relays, and discrete command signals beyond its native pin count. Its 16 configurable ports provide a compact interface between low-voltage control logic and field-panel wiring, while the 400 kHz I2C connection allows one bus to address multiple peripheral functions. The 2.3 V to 5.5 V operating range supports both 3.3 V and 5 V controller platforms. Because the verified operating-temperature range is unavailable, qualification for a specific industrial environment remains to be confirmed against the manufacturer datasheet.
推荐
Sensor Aggregation and Discrete Inputs
The PCA9535PW can consolidate discrete sensor outputs, interlocks, and contact closures into a 16-port interface without allocating separate microcontroller pins to every signal. Its configuration registers allow firmware to select input or output operation, while an input change can generate an interrupt so the host can service relevant events instead of continuously polling all ports. The interface operates up to 400 kHz on I2C and from 2.3 V to 5.5 V. External input conditioning or pull-ups should be added wherever a sensor output is open-drain or the PCA9535’s lack of internal I/O pull-ups would otherwise leave the input undefined.
推荐
LED and Human-Interface Control
The PCA9535PW fits LED status indicators, pushbuttons, selector inputs, and small display-control interfaces because each of its 16 ports can be configured as an output or input. A host processor can update several panel indicators through the same 400 kHz I2C bus rather than through individual serial GPIO lines. When driving LEDs, the total current, voltage drop, and aggregate port current must remain within the verified device limits. For open-collector indicators, external pull-ups are required because the PCA9535 has no internal I/O pull-up resistors.
推荐
Embedded Instrument Control
The PCA9535PW can extend a compact instrument or test fixture with banked controls, trigger inputs, relays, and status LEDs while conserving the host processor’s direct GPIO resources. Its interrupt output supports event-driven operation, which is useful when the system should respond promptly to a switch or interlock without frequent polling. The low-power PCA9535 variant can also reduce standby consumption when ports are held low. The engineer should still verify operating-temperature limits, port-drive capability, and EMC requirements before using it in a safety- or measurement-critical instrument.
推荐
Programmable Logic Controller I/O
The PCA9535PW is suitable for small PLC and embedded automation modules that need a compact, serial-addressable bank of 16 digital I/O points. The I2C interface allows the controller to configure port direction and read the input state efficiently at up to 400 kHz, while the interrupt output provides an event-driven path for connected field signals. Its 24-pin TSSOP package supports conventional surface-mount assembly, and the 2.3 V to 5.5 V range accommodates common control voltages. For long cable runs or noisy industrial wiring, appropriate isolation, protection, and signal-conditioning circuits should be added outside the device.
推荐
Low-Power Portable Device Interface
The PCA9535PW can reduce I/O-pin pressure in compact embedded products by controlling LEDs, buttons, and low-current peripherals over I2C. Its verified standby-current specification is no more than 1 µA, and removal of the internal I/O pull-up resistors reduces power consumption when ports are held low, making it useful in battery-conscious equipment. The 2.3 V minimum supply voltage supports low-voltage logic domains. Actual battery-life benefit depends on port state, external resistor values, and how often the host reads or writes the expansion registers.
推荐
推荐产品汇总
工程参考数据： PCA9535PW ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | PCA9535CPW | PCA9555PW | PCA9555PW | PCA9535PWR |
|---|---|---|---|---|---|
| Package | 24-TSSOP | 24-TSSOP | 24-TSSOP | 24-TSSOP | 24-TSSOP |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Texas Instruments | NXP Semiconductors |
| GPIO Port Count | 16 ports | 16 ports | 16 ports | 16 ports | 16 ports |
| I2C Interface | I2C/SMBus | I2C/SMBus | I2C/SMBus | I2C/SMBus | I2C/SMBus |
关键差异点
- Lower-power choice than the PCA9555 family （对比 NXP PCA9555PW)
- Direct NXP family sourcing （对比 Texas Instruments PCA9555PW)
- Event-driven input monitoring （对比 PCA9535CPW)
设计说明
Do not assume the PCA9535PW has the same internal pull-up behavior as the PCA9555. NXP states that the PCA9535 removes the internal I/O pull-up resistors to reduce power consumption when ports are held low. Add external pull-ups wherever a port reads an open-drain signal or must remain defined during reset; otherwise, a floating input can create an unintended interrupt or unstable digital state.
Place the PCA9535PW close to the I2C controller and its associated pull-up network to minimize trace length and sensitivity to noise. Route the 16 port traces away from high-current switching paths, and provide a solid ground reference. The interrupt output should also be routed with suitable signal-integrity practices because long PCB traces can couple noise into a low-current notification signal.
Budget the PCA9535 supply current from the verified operating range of 2.3 V to 5.5 V, including port-drive current, pull-up current, and leakage. The verified standby-current limit is 1 µA, but average system consumption may be much higher during active I/O transitions. Decouple the device locally and validate the external pull-up values against bus capacitance, rise time, and the maximum current permitted by the selected port configuration.
Although the PCA9535PW is described as pin-to-pin and I2C-address compatible with the PCF8575, the software models are not identical. NXP explicitly states that software changes are required for the PCA9535 enhancements. Review register addresses, input-port semantics, polarity inversion, and interrupt clearing before reusing a PCF8575 driver or treating a hardware substitution as firmware-compatible.
合规信息
The verified excerpts confirm active production and identify environmental and shipping information sections, but they do not provide explicit compliance declarations. Obtain the current NXP or distributor compliance documentation for the exact orderable part.
