PCA9539DB - 16-Bit I/O Expander, 2.3-5.5V | Texas Instruments
部品番号: PCA9539DB ✓ 生産中PCA9539DB 概要
An I/O expander is an interface IC that extends the usable input/output count of a microcontroller or other embedded processor. It sits in the hierarchy of semiconductor, interface IC, I/O expander, and parallel I/O controller. Rather than requiring a microcontroller to devote many pins to switches, buttons, relays, or indicators, the PCA9539DB transfers those signals over I2C while providing configurable input and output registers.
The PCA9539DB provides interrupt, reset, and configuration registers. Its interrupt output is open-drain and active-low, allowing the device to signal a change in an input state without continuous software polling. Maximum standby current is 1 µA, making the device suitable for low-power embedded systems that need additional control lines while minimizing inactive-state consumption.
The device connects to a two-wire bidirectional I2C or SMBus interface and operates across a 2.3 V to 5.5 V supply range. This voltage range supports both 3.3 V and 5 V system architectures. The available 400 kHz bus specification provides a practical operating rate for control-oriented peripheral expansion where throughput requirements are modest and deterministic bus behavior is more important than maximum serial bandwidth.
Typical uses include expanding GPIO on a compact embedded controller, reading grouped switch or sensor inputs, driving external indicator or relay-control signals, and building a modular peripheral interface around an I2C bus. The active-low open-drain interrupt is particularly useful when the host must sleep between events and wake when an input changes.
Designers should account for I2C pull-up resistors, address selection, and the electrical requirements of whichever loads connect to P0 through P15. The PCA9539DB differs from the PCA9555 because it omits the internal I/O pull-up resistors, replaces the A2 address input with RESET, and uses a different address range. This reduced loading can lower power consumption when the I/O lines are held low, but external pull-ups may be required where the application depends on them.
This product record consolidates the verified manufacturer and distributor information into an engineering-focused resource covering device function, package data, sourcing links, application context, and practical replacement constraints. Only confirmed drop-in alternatives with the same package and electrical behavior are presented; functional equivalents requiring a different footprint are not mislabeled as drop-in replacements.
ドロップイン代替品: PCA9539DB — 同一パッケージでピン互換。PCBの作り直しが必要な異なるパッケージの部品は除外されています。
この製品に利用可能なドロップイン代替品はありません。
代替品をリクエストPCA9539DB 仕様
| Number of I/O | 16 bits |
| 動作電源電圧 | 2.3 V to 5.5 V |
| I2C Bus Frequency | 400 kHz |
| インターフェースタイプ | I2C/SMBus |
| Maximum Standby Current | 1 µA |
| Interrupt Output Type | Open-drain, active-low |
| ピン数 | 24 pins |
| パッケージ | 24-pin SSOP (DB) |
| Package Body Width | 5.30 mm |
| 実装タイプ | Surface mount |
| Reset Pin | Yes |
| Interrupt Pin | Yes |
| Configuration Registers | Yes |
| Internal I/O Pull-Up Resistors | None |
PCA9539DB 5.30 mm ピン配置ガイド
PCA9539DB (5.30 mm パッケージ) のピン配置。 ピン番号、機能、接続図はメーカーのデータシートで定義されています。正確なフットプリントとはんだ付けのガイドラインについては、データシートを参照してください。
詳細なピン配置データはありません: PCA9539DB.
詳細は データシート をご参照ください。
主な用途
PCA9539DB の用途: 6 件s: Embedded GPIO Expansion, Industrial Switch and Control Panels, LED and Indicator Control, Sensor and Digital Input Hub, Battery-Powered Portable Equipment, Communication and Network Equipment.
Embedded GPIO Expansion
The PCA9539DB is appropriate when a compact microcontroller needs additional general-purpose input/output lines without dedicating 16 package pins to external control functions. It connects over the 2.3-5.5 V I2C/SMBus interface and presents 16 configurable parallel ports through the 24-pin SSOP device. This is particularly useful in space-constrained controllers where adding a larger MCU solely for a few external signals would increase board area. The 400 kHz bus rate is suitable for slow control and status traffic, while the 1 µA maximum standby current helps limit inactive-state consumption. Design the firmware around a register-based access model and ensure that the host bus pull-ups, reset behavior, and address configuration are handled consistently.
おすすめ
Industrial Switch and Control Panels
The PCA9539DB can consolidate switch inputs, mode controls, and output indications in an industrial control panel where the host controller is better used for higher-level processing. Its 16-bit I/O capability and 2.3-5.5 V operating range suit common 3.3 V and 5 V control electronics. The active-low, open-drain interrupt allows the controller to react when a monitored input changes rather than repeatedly reading the expander. Because the interrupt line is open-drain, it requires an appropriate pull-up and suitable wiring. Engineers should also design for industrial noise, connector transients, and input conditioning, as those protection requirements are separate from the PCA9539DB's verified bus and supply specifications.
おすすめ
LED and Indicator Control
The PCA9539DB can expand a microcontroller's available output count for grouped LEDs, status indicators, and alarm signals. Sixteen ports provide a straightforward way to organize panel indicators without consuming the host's dedicated GPIO pins, while the 400 kHz I2C rate is adequate for ordinary on/off and blinking sequences. Supplying the indicator circuitry from a suitable rail while observing the PCA9539DB's 2.3-5.5 V operating range keeps the serial interface compatible with common control voltages. For high-current LED loads, use suitable driver transistors rather than driving the outputs beyond their published limits. The verified extracts do not provide every output drive specification, so the manufacturer datasheet should be consulted before assigning absolute-current or LED-drive duties.
おすすめ
Sensor and Digital Input Hub
The PCA9539DB can act as a remote input hub for digital sensors, limit switches, interlocks, and configuration straps when those signals are too numerous or physically distant from the main controller. Its 16 parallel I/O lines are accessed through I2C, and the active-low interrupt output provides a practical event-driven wake-up path. This arrangement can reduce host pin count and the amount of wiring around a distributed panel. Use the reset and configuration registers as intended, confirm the device address in system software, and provide the bus with appropriate pull-up resistance. External protection may be required for long cable runs or exposed contacts because the verified source material does not specify the complete industrial transient ratings.
おすすめ
Battery-Powered Portable Equipment
The PCA9539DB is suited to portable equipment requiring several low-speed controls while the main controller spends substantial time inactive. Its maximum standby current of 1 µA and lack of internal I/O pull-up resistors reduce standby loading when the external lines are held low, as stated by Texas Instruments. The device can also notify the host through its active-low interrupt, avoiding continuous polling in suitable designs. A 2.3-5.5 V supply range allows use in both 3.3 V and 5 V portable architectures. Battery-system designers should still calculate the complete sleep-path current, including pull-up resistors, level shifters, and any attached loads. The verified information does not provide every operating-current condition, so those details must be taken directly from the manufacturer datasheet.
おすすめ
Communication and Network Equipment
The PCA9539DB can provide auxiliary control lines in network or communication equipment where the main processor needs to monitor and control status LEDs, relay paths, alarm inputs, or equipment-enable signals. The 16-bit I2C interface reduces pin consumption while the 400 kHz bus speed remains practical for low-bandwidth supervisory functions. In systems with noisy power systems, separate the expander's supply and ground routing from switching nodes, observe the 2.3-5.5 V supply requirement, and confirm all input levels remain compatible. The active-low open-drain interrupt can be connected to a controller interrupt resource when events must be reported promptly. Its open-drain implementation also requires the correct pull-up arrangement and should be checked against the system interrupt topology.
おすすめ
おすすめ製品の概要
エンジニアリング参考データ: PCA9539DB — 比較、設計ガイダンス、コンプライアンス情報。
選定ガイド
代替品との比較
| パラメータ | この製品 |
|---|---|
| Brand | Texas Instruments |
| Package | 24-pin SSOP (DB) |
| Number of I/O | 16 bits |
| Operating Supply Voltage | 2.3 V to 5.5 V |
| I2C Bus Frequency | 400 kHz |
| Interface | I2C/SMBus |
| Maximum Standby Current | 1 µA |
| Interrupt Output | Open-drain, active-low |
| Internal I/O Pull-Ups | None |
| Special Features | Interrupt, reset, and configuration registers |
主な差別化要因
- Low-power standby operation （vs PCA9555)
- Dedicated hardware reset function （vs PCA9555)
- Compact 16-bit expansion over a two-wire bus （vs TCA9539PWR)
設計ノート
Use the PCA9539DB within its verified 2.3 V to 5.5 V operating-supply range and place its decoupling capacitors close to the supply and ground pins according to the manufacturer layout guidance. Account for bus pull-up current in the standby-power budget because the device omits internal I/O pull-ups, but those pull-ups and any attached external loads can dominate current when the I/O lines are held low. Do not infer the full operating-current or output-drive limits from the available 1 µA standby specification; consult the manufacturer datasheet before assigning heavier loads.
Keep the I2C routing compact and continuous, with the SCL and SDA traces routed away from switching nodes and high-current return paths. The verified architecture supports 400 kHz operation, but layout margin remains important because bus rise time depends on capacitance, pull-up resistance, and external loading. Place pull-up resistors at a location consistent with the system bus topology, and provide the active-low open-drain interrupt with its own appropriate pull-up. Review the manufacturer package drawing and pin configuration before finalizing the 24-pin SSOP footprint.
Do not treat the PCA9555 as a register-for-register drop-in substitute. Texas Instruments identifies three material differences: the PCA9539 removes the internal I/O pull-up resistors, replaces A2 with RESET, and uses a different address range. A replacement PCB or firmware must account for those distinctions. Also, the open-drain interrupt cannot directly drive a logic-high signal without a pull-up, and the selected pull-up value must balance low-level current against bus rise-time requirements.
コンプライアンス情報
The supplied verified extracts do not state the component-specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status, so these fields remain unknown.
