PCA9536DG4 - 4-Bit I2C I/O Expander | Texas Instruments
MPN： PCA9536DG4 ✓ 啟用中PCA9536DG4 概覽
An I/O expander is an interface IC that converts a serial control bus into additional parallel input or output lines. The PCA9536 belongs to the I2C interface-controller hierarchy and is used when a microcontroller has too few GPIO pins for sensors, switches, indicators, relays, or other external hardware. Its configuration registers allow each port line to be programmed as an input or output, making the device useful in designs where the exact pin direction must be established by firmware.
The PCA9536 provides a 2.3 V to 5.5 V operating supply range, I2C/SMBus communication up to 400 kHz, and low standby current, with a maximum standby current of 1 µA. The 8-SOIC package provides a compact surface-mount footprint for applications that need more I/O capacity without adding a large number of individual GPIO connections. The device also supports remote I/O expansion for common microcontroller families through the I2C interface.
The PCA9536 uses separate serial clock and serial data lines, SCL and SDA, for communication with the controller. Configuration registers determine whether the four port lines operate as inputs or outputs, while output data registers control the state of output pins. This arrangement allows firmware to scan inputs, update outputs, and implement debounce or device-specific control routines through a shared serial bus.
Typical applications include low-pin-count industrial controllers, sensor and relay interface boards, compact consumer devices, LED or switch control systems, and microcontroller designs requiring additional GPIO lines. When using the PCA9536, confirm the controller's I2C address configuration and the intended input or output mode for each port pin. The host system must also account for pull-up requirements and electrical limits when connecting external signals.
The main design consideration is bus and I/O planning. Assign addresses and directions consistently across all connected devices, keep external signals within the device's specified limits, and use appropriate pull-up resistors on SCL and SDA. Because the PCA9536DG4 is only an I/O expander, functions such as analog conversion, level shifting, and high-current drive usually require additional components.
This product page combines the manufacturer device description with distributor listing information and practical application guidance for engineers evaluating the PCA9536DG4. It also identifies compatible same-package alternatives, summarizes the key register and interface considerations, and highlights where additional external circuitry is needed for complete embedded I/O designs.
直接替換替代品，適用於 PCA9536DG4 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： PCA9536DG4 （相同外形與佔位） — 差異在於 Configuration Registers, Package, Product Type.
PCA9536DGKRG4
✅ 直接替換📋 參考替代品（不在目錄中）
PCA9536DR
✅ 直接替換聯絡詢價
查看資料表 →PCA9536D
✅ 直接替換聯絡詢價
查看資料表 →PCA9536DG4R
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
PCA9536DGS
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
PCA9536DG4 規格
| Product Type | 4-bit I2C/SMBus remote I/O expander |
| Number of I/O Lines | 4 |
| Operating Supply Voltage Range | 2.3 V to 5.5 V |
| I2C/SMBus Maximum Frequency | 400 kHz |
| Standby Current | 1 uA maximum |
| 供應電流 | 0.15 mA maximum |
| Maximum Operating Temperature | 85 C |
| 封裝 | 8-pin SOIC |
| 介面 | I2C/SMBus |
| Serial Clock Pin | SCL |
| Serial Data Pin | SDA |
| Configuration Registers | Yes |
| 安裝類型 | Surface Mount |
PCA9536DG4 8-pin soic 腳位配置指南
PCA9536DG4（8-pin soic 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： PCA9536DG4.
請參閱 資料表 以查看完整腳位配置。
典型應用
PCA9536DG4 適用於 6 應用s: Low-Pin-Count MCU I/O Expansion, Industrial Sensor Interface, LED and Indicator Control, Relay and Discrete Control Signals, Compact Consumer Control Board, Communications Equipment Port Control.
Low-Pin-Count MCU I/O Expansion
The PCA9536DG4 fits designs in which a microcontroller has reserved most of its GPIO pins for core functions. Its four programmable I/O lines can be assigned individually as inputs or outputs, while SCL and SDA provide control over the complete port through the I2C bus. The 2.3 V to 5.5 V operating range supports common embedded supply levels, and the 400 kHz interface rate allows efficient updates when several devices share the bus. A host MCU such as one of the STM32 families can read switch states or control external logic without consuming additional direct GPIO pins.
推薦
Industrial Sensor Interface
The PCA9536DG4 can collect digital sensor or limit-switch information when an industrial controller lacks direct input pins. Each of the four lines can be configured as an input, allowing status, alarm, interlock, or presence signals to be monitored through SCL and SDA. The device operates from 2.3 V to 5.5 V and supports bus communication up to 400 kHz, which helps preserve controller resources for more demanding processing. Designers should add appropriate input conditioning, isolation, or protection where field wiring exposes the board to transients or unsuitable logic levels.
推薦
LED and Indicator Control
The PCA9536DG4 is useful for grouped status indicators, panel lamps, or low-current LED controls when the controller cannot drive them directly. Its configuration registers let firmware assign each of the four outputs independently, while the serial interface keeps the wiring compact. The 1 uA maximum standby current helps maintain low quiescent demand in intermittently powered equipment, although the complete system must also account for output-state leakage and any driver circuitry. A separate transistor stage is appropriate when an LED bank requires more current than the I/O port can safely source.
推薦
Relay and Discrete Control Signals
The PCA9536DG4 can provide logic-level control and status signals for relay boards, contactors, or discrete control circuits. Its four configurable outputs reduce the number of direct host-controller connections, while firmware-controlled direction and data registers simplify sequencing. The 2.3 V to 5.5 V range permits operation in embedded 3.3 V and 5 V systems, and the 400 kHz bus rate supports quick updates. Actual inductive loads should be isolated from the I/O pins with suitable transistors, flyback protection, and grounding designed for the application.
推薦
Compact Consumer Control Board
In a compact consumer device, the PCA9536DG4 can add configurable buttons, mode indicators, or accessory-control lines without requiring a larger microcontroller package. The small 8-pin SOIC format supports dense PCB layouts, and the I2C interface allows the host processor to update several port lines using only SCL and SDA. Its low standby current is advantageous for energy-conscious portable products, while the 2.3 V minimum operating voltage accommodates lower-voltage logic systems. Firmware should define defaults for port direction and output state so the external hardware remains predictable during reset.
推薦
Communications Equipment Port Control
The PCA9536DG4 can provide local control and status lines in communications equipment where the main processor manages an external transceiver or modem. Four inputs can monitor module-ready, fault, or link-state signals, while outputs can select modes or acknowledge peripheral events. Supporting I2C operation up to 400 kHz permits efficient register access without dedicating four host GPIO pins to each peripheral. Designers should keep control traces away from sensitive analog paths and apply the manufacturer's input and output limits when interfacing with powered modules.
推薦
推薦產品摘要
工程參考資料，適用於 PCA9536DG4 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | PCA9536DGKRG4 | PCA9536DR | PCA9536D | PCA9536DG4R | PCA9536DGS |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC |
| Product Function | 4-bit I2C/SMBus remote I/O expander | 4-bit I2C/SMBus remote I/O expander | 4-bit I2C/SMBus remote I/O expander | 4-bit I2C/SMBus remote I/O expander | 4-bit I2C/SMBus remote I/O expander | 4-bit I2C/SMBus remote I/O expander |
| Number of I/O Lines | 4 | 4 | 4 | 4 | 4 | 4 |
| Operating Supply Voltage | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V |
| I2C/SMBus Maximum Frequency | 400 kHz | 400 kHz | 400 kHz | 400 kHz | 400 kHz | 400 kHz |
主要差異化特點
- Compact four-line expansion in an 8-pin SOIC (對比PCA9554DWR)
- Same core I2C/SMBus interface and supply range across the PCA9536 options (對比PCA9536DR)
- Low standby current for embedded and portable control boards (對比PCA9536DGKRG4)
設計說明
Place the PCA9536DG4 close to the controller and the devices connected to its four I/O lines. Keep SCL and SDA routing short, avoid long stubs, and route the bus away from switching nodes and high-current paths. The SOIC footprint requires adequate solder-joint clearance and inspection access, particularly in densely populated consumer equipment.
Connect the supply pins to the device's specified operating range of 2.3 V to 5.5 V and place local supply decoupling close to the IC. The device's maximum supply current is 0.15 mA, but total board demand also includes pull-up resistors and attached external circuits. Confirm that the host controller's I2C pins and pull-up network produce valid logic levels at the expander.
Do not assume that every PCA9536 orderable suffix is automatically interchangeable. Verify the package, pin names, electrical limits, temperature range, and device address before substitution. Also configure each port direction explicitly in firmware and provide safe defaults during reset, because external pull resistors can otherwise influence the state of an input or output line.
合規資訊
The available product-page and distributor excerpts do not state suffix-specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Review the current TI compliance declarations for the exact PCA9536DG4 order code.