PCA9534DBR - 8-Bit I2C GPIO Expander | Texas Instruments
料号： PCA9534DBR ✓ 量产中PCA9534DBR 概述
An I/O expander is a low-power interface IC used to extend the number of general-purpose input/output lines available to an embedded system. Its hierarchy is GPIO expander, I/O expander, interface IC, and semiconductor. Instead of dedicating eight host-controller pins to each group of inputs and outputs, a system can place the PCA9534DBR on an I2C or SMBus and read or write its ports through register addresses. This is especially useful in compact industrial, consumer, communications, and embedded-control equipment where connector count and PCB area constrain the host MCU.
Key features include eight general-purpose I/O ports, programmable addressing through A0, A1, and A2, and an open-drain interrupt output. The official Texas Instruments product information identifies a 2.3 V to 5.5 V VCC range and a 400 kHz I2C bus rate. Independent source information identifies the device as a CMOS 16-pin component and gives an operating temperature range of -40 °C to 85 °C. The SSOP package also makes the part suitable for surface-mount production and PCB footprint reuse where the package is verified against the alternate device.
The PCA9534 architecture separates port data from configuration and addressing functions. A0, A1, and A2 hardware pins program the device address, while the serial interface provides access to the input, output, polarity, and configuration registers. The interrupt output allows the host to react when a selected input changes rather than continuously polling every port. Unlike devices with continuously enabled internal input pull-ups, the PCA9534 is noted by NXP as having no internal I/O pull-up resistor, reducing power consumption when outputs are held low; external pull-ups may therefore be required according to the application circuit.
Typical uses include remote push-button inputs, LED and relay-control outputs, sensor and switch interfaces, backlight control, and expansion of a host processor's limited GPIO. The 400 kHz bus rate supports routine control traffic rather than high-bandwidth data transfer. Firmware should address each expander through its hardware-configured base address and initialize the configuration and polarity registers before changing port directions.
Designers should verify pull-up requirements, address uniqueness, bus capacitance, and interrupt polarity for every connected device. Pull-up resistors should be sized for the lowest operating voltage and the complete bus population. I2C trace length and routing also matter because this low-power expander commonly shares a bus with sensors, EEPROMs, and other peripherals. Software for PCF8574-based designs may require changes when migrating to PCA9534 because the enhanced register behavior is not identical despite hardware compatibility.
This product record combines verified manufacturer and distributor information, same-footprint alternatives, application guidance, and design cautions. It also distinguishes genuine pin-compatible choices from devices that only have similar functions, helping engineers shorten replacement evaluation without overlooking firmware and electrical differences.
直接替换替代料： PCA9534DBR ——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： PCA9534DBR （相同外形与封装尺寸） ——差异在于 Package, Configuration Registers, Interrupt Output, Interface, Operating Temperature.
PCA9554DBR
✅ 直接替换联系询价
查看数据手册 →PCA9536DR
✅ 直接替换联系询价
查看数据手册 →TCA9554APWR
✅ 直接替换📋 参考替代料（不在目录中）
PCA9534DBR 规格参数
| Device Type | 8-bit I2C/SMBus I/O expander |
| Number of GPIO Ports | 8 ports |
| Supply Voltage Range | 2.3 V to 5.5 V |
| I2C Bus Frequency | 400 kHz |
| Bus Interface | I2C/SMBus |
| Technology | CMOS |
| 工作温度 | -40 °C to 85 °C |
| 封装 | 16-pin SSOP, 7.50 mm body |
| 安装类型 | Surface mount |
| Address Configuration Pins | 3 pins: A0, A1, and A2 |
| Maximum Devices per Bus | 8 devices |
| Interrupt Output | Available |
| Configuration Registers | Available |
| Internal I/O Pull-Up Resistors | Not fitted |
| PCF8574 Hardware Compatibility | Pin-to-pin and I2C address compatible; software changes required |
PCA9534DBR 16-pin ssop, 7.50 mm body 引脚配置指南
PCA9534DBR（16-pin ssop, 7.50 mm body 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： PCA9534DBR.
请参阅 数据手册 以查看完整引脚配置。
典型应用
PCA9534DBR 适用于 6 应用s: Industrial Control Panel Expansion, Remote Push-Button and Switch Interface, LED and Relay Control, Sensor and Peripheral Hub, Embedded Communications Equipment, Battery-Powered Low-Power Controller.
Industrial Control Panel Expansion
The PCA9534DBR fits industrial control panels that need more switch inputs and indicator outputs than the host controller can provide directly. Its eight general-purpose ports can be configured individually, while A0, A1, and A2 permit as many as eight devices to share the I2C bus. With a verified 2.3 V to 5.5 V operating range and -40 °C to 85 °C temperature rating, it supports both 3.3 V and 5 V control electronics. Place pull-ups for the complete bus, configure polarity for the attached logic, and use the interrupt output to report changed inputs without continuous polling. Because the device has no internal I/O pull-up resistors, any required input or open-drain pull-ups must be fitted externally.
推荐
Remote Push-Button and Switch Interface
PCA9534DBR provides a compact remote interface for push buttons, limit switches, selectors, and interlocks. Eight ports can be configured as inputs, allowing the controller to read multiple discrete states through the 400 kHz I2C interface rather than reserving one MCU pin per switch. The interrupt output can signal a transition after the host enables the relevant detection function. External pull-ups may be required because the PCA9534 does not include the internal I/O pull-up resistors associated with PCA9554. Firmware should debounce the mechanical contacts, initialize the polarity and configuration registers, and confirm that the shared bus pull-up value remains valid at the system's lowest operating voltage.
推荐
LED and Relay Control
The PCA9534DBR can drive eight LED indicators, relay-control inputs, or other low-current digital loads when the downstream circuitry meets the device's electrical limits. Its output ports are controlled through I2C registers, reducing host-controller pin consumption in equipment with many status indicators. The 400 kHz bus rate is appropriate for ordinary command and status traffic rather than high-speed display data. Designers must verify output current, voltage levels, inductive-load protection, and any required external drivers. If an attached relay coil exceeds the port capability, use a suitable transistor or driver stage. The expander also supports configurable polarity, which can simplify active-high versus active-low status interfaces.
推荐
Sensor and Peripheral Hub
PCA9534DBR can act as a discrete peripheral hub alongside sensors, EEPROMs, and other I2C components when a system needs additional digital control or status lines. Its three hardware address pins reduce the need for software-only addressing and allow up to eight devices to coexist on one bus. The interrupt output is useful when a peripheral changes state asynchronously, while the 400 kHz interface supports routine control-register traffic. The bus must remain within its capacitance and pull-up limits after adding the expander and all other devices. Designers should also budget I/O voltage compatibility with each attached peripheral and avoid relying on the PCA9534's missing internal pull-ups as a substitute for deliberate resistor selection.
推荐
Embedded Communications Equipment
In communications equipment, PCA9534DBR can expand status LEDs, configuration switches, modem-control lines, or module interface signals while keeping the main processor's pin count manageable. The 16-pin SSOP package suits compact surface-mount boards, while the 2.3 V to 5.5 V range accommodates common telecom and networking logic levels. Use separate address assignments for every expander on a shared 400 kHz bus and confirm that all attached devices support the bus voltage. If the bus is long or heavily populated, review pull-up resistance, capacitance, ringing, and the need for a buffer such as PCA9515A. Software migration should preserve the PCA9534 register model rather than assuming that every pin-compatible expander is software-compatible.
推荐
Battery-Powered Low-Power Controller
The PCA9534DBR is appropriate for battery-powered equipment when the design benefits from avoiding continuously enabled internal I/O pull-ups. NXP documentation identifies the absence of the PCA9534's internal pull-up resistor as a distinction from PCA9554 and notes that this reduces power consumption when I/Os are held low. The device still operates at only a 2.3 V to 5.5 V supply range and uses a 400 kHz two-wire interface, helping minimize both pin count and bus complexity. A low-power implementation should nevertheless disable unused ports, account for external pull-up current, use the interrupt output to reduce polling, and measure the complete rail rather than relying on the expander datasheet alone to predict battery life.
推荐
推荐产品汇总
工程参考数据： PCA9534DBR ——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 | PCA9554DBR | PCA9536DR | TCA9554APWR | PCA9554PW | PCA9534D |
|---|---|---|---|---|---|---|
| Package | 16-pin SSOP | 16-pin SSOP - same | 16-pin SSOP - same | 16-pin SSOP - same | 16-pin SSOP - same | 16-pin SO-16 - same pin count |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | NXP Semiconductors | NXP Semiconductors |
| I/O Port Count | 8 ports | 8 ports | 8 ports | 8 ports | 8 ports | 8 ports |
| Bus Protocol | I2C/SMBus | I2C/SMBus | I2C/SMBus | I2C/SMBus | I2C/SMBus | I2C/SMBus |
关键差异点
- No internal I/O pull-up resistor （对比 PCA9554DBR)
- Established PCF8574 hardware migration path （对比 TCA9554APWR)
- Lower minimum operating voltage than TCA9554APWR （对比 TCA9554APWR)
设计说明
Route the I2C clock and data as a compact, matched-length bus, and place the required pull-up resistors near the bus master or according to the calculated worst-case location. Include the PCA9534DBR in the complete bus-capacitance and pull-up-current calculation. The PCA9534 has no internal I/O pull-up resistors, so inputs or open-drain outputs require deliberate external pull-up arrangements. Confirm that pull-up voltage remains compatible with every 2.3 V to 5.5 V device on the bus.
Do not treat hardware compatibility as software compatibility. Texas Instruments states that PCA9534 is pin-to-pin and I2C-address compatible with PCF8574, but software changes are required because PCA9534 adds enhanced registers. Likewise, PCA9554-family alternatives differ in internal pull-up behavior. Before substituting a device, compare register addresses, direction handling, polarity behavior, interrupt logic, address selection, and existing driver assumptions. Validate the revised design at the minimum, nominal, and maximum system supply voltages.
Estimated power use must include the external pull-up network because the PCA9534 does not contain the internal I/O pull-ups found in PCA9554. For an open-drain output held low, pull-up current is approximately VBUS divided by the total pull-up resistance; for example, a 4.7 kΩ pull-up on a 3.3 V rail dissipates about 0.70 mA. This is an engineering estimate, not a datasheet specification. Use the actual bus voltage, resistance, and duty cycle, and account for leakage and attached-device currents when comparing battery-life alternatives.
合规信息
The supplied verified excerpts do not explicitly state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Because PCA9534DBR is an interface IC rather than an automotive-qualified variant in the supplied data, AEC-Q100 is recorded as not applicable.
