PCF8574AN - 8-Bit I/O Expander | Texas Instruments | DIP
部品番号: PCF8574AN ✓ 生産中PCF8574AN 概要
A remote I/O expander reduces the number of general-purpose I/O pins required on a microcontroller, programmable logic controller, or other embedded controller. Eight digital lines can be distributed across a remote circuit board, allowing buttons, indicators, logic inputs, or other digital signals to connect to a shared two-wire bus. The PCF8574AN therefore reduces package size and routing complexity when a design requires more digital interface lines than the host controller provides directly.
The verified dataset supplied for this product contains no manufacturer-document specifications or distributor records. Consequently, operating voltage, address range, output-drive capability, clock frequency, logic thresholds, quiescent current, and environmental ratings are not asserted on this page. These parameters must be confirmed from the applicable Texas Instruments manufacturer datasheet before the IC is used in a new schematic, PCB layout, firmware configuration, or safety- and reliability-critical design.
The PCF8574AN is typically associated with 5 V and 3.3 V embedded systems, but the actual supported supply range and interface levels are deliberately left unspecified here because no verified manufacturer data was provided. Logic-level compatibility must be evaluated using the authoritative input thresholds, output leakage, and output-driver specifications rather than nominal rail voltage alone.
Typical design candidates include general-purpose microcontroller I/O expansion, programmable controller input modules, front-panel button and indicator handling, and simple industrial control boards. An I2C or other two-wire host bus may be shared by multiple expanders only after address allocation, electrical loading, pull-up requirements, and bus-speed limits have been verified.
The primary layout concern is the two-wire bus. Place pull-up resistors and decoupling capacitors close to the appropriate bus endpoints, keep the clock and data traces short, and confirm that every connected device can tolerate the selected voltage and clock rate. Firmware must also establish the device address and configure each line as input or output before external hardware is energized.
This page combines an authenticity-first specification record with procurement, replacement, selection, and design-intent guidance. Because the retrieved distributor and cross-reference searches returned no records, market pricing, lifecycle availability, exact pin naming, and additional drop-in alternatives remain explicitly unverified rather than being inferred from similar devices.
ドロップイン代替品: PCF8574AN — 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。
このシリーズのバリエーション
同一シリーズでドロップイン互換のモデル: PCF8574AN （同一形状・フットプリント） — 相違点: Mounting Type, Function, Interface, Interrupt Output, Package.
PCF8574PWR
✅ ドロップイン ⚠️ 仕様未検証価格はお問い合わせください
データシートを見る →PCF8574AP
✅ ドロップイン ⚠️ 仕様未検証📋 参考代替品（カタログ未掲載）
PCF8574AN 仕様
| 仕様はありません |
PCF8574AN standard ピン配置ガイド
PCF8574AN (standard 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: PCF8574AN.
詳細は データシート をご参照ください。
主な用途
PCF8574AN の用途: 6 件s: Microcontroller Digital I/O Expansion, Programmable Controller Input Module, Front-Panel Button and Indicator Interface, Industrial Digital Control Interface, Remote Sensor and Switch Aggregation, Test and Fixture Control Interface.
Microcontroller Digital I/O Expansion
The PCF8574AN is architecturally suited to expanding the number of digital lines available to a microcontroller without dedicating eight direct host pins to switches, indicators, or logic signals. In a typical circuit, the host communicates with the expander through the serial bus, writes a port configuration register, and then reads or updates individual I/O states. The verified dataset does not specify the interface protocol, clock limit, address count, or logic thresholds, so the final design must confirm host-bus compatibility, pull-up values, and pin behavior from the manufacturer datasheet before layout release.
Programmable Controller Input Module
A PCF8574AN-based module can place digital field inputs farther from a programmable logic controller or embedded controller, reducing the number of wiring channels required in the controller enclosure. Eight remote digital lines can represent limit switches, interlocks, selectors, or other binary conditions. The exact input thresholds and address behavior are unavailable in the verified dataset, so field-interface compatibility must be established using the authoritative voltage thresholds and isolation requirements rather than assuming standard 3.3 V or 5 V logic levels.
Front-Panel Button and Indicator Interface
The PCF8574AN can be evaluated for front-panel digital I/O consolidation, where buttons and indicator states are distributed over a serial connection to the main controller. This approach can reduce direct host-controller pin usage and simplify the wiring burden compared with connecting every panel signal individually. Designers should verify the power-on state of every output, the allowable capacitive load on each indicator, input debounce requirements, and the behavior of the PCF8574AN A-family reset logic before relying on panel indications during startup.
Industrial Digital Control Interface
A PCF8574AN may serve as a local digital interface beside a programmable controller in industrial equipment, with eight lines handling discrete command or status functions. It is most appropriate when the signals are ordinary digital levels and the device is not the sole safety barrier for a hazardous process. Because the verified dataset contains no operating-temperature, supply-voltage, creepage, isolation, or output-drive information, industrial suitability requires comparison with the applicable Texas Instruments datasheet and the machine's electrical-safety requirements.
Remote Sensor and Switch Aggregation
The PCF8574AN can aggregate several discrete switch or sensor contacts into one serial bus connection, reducing wiring complexity in a distributed control assembly. Eight inputs can represent contact closures, position sensors, or binary status signals when their voltage levels fall within the verified input thresholds. Because no threshold, leakage-current, clock-rate, or bus-loading data was supplied, the implementation must include suitable pull-up or level-conditioning arrangements and must verify that the aggregate capacitive loading remains within the confirmed bus limits.
Test and Fixture Control Interface
A PCF8574AN can provide compact digital control for a test fixture when the fixture includes simple pass, fail, mode, or fixture-enable signals that can be controlled by a host over a shared serial bus. This can reduce the number of host-controller I/O pins and create a repeatable software-controlled interface. Engineers should confirm the maximum clock rate, logic thresholds, output-state behavior during reset, and drive limits before using the IC for fixtures where an incorrect output could create an unsafe or destructive test condition.
エンジニアリング参考データ: PCF8574AN — 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 | PCF8574P | PCF8574AP |
|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | PDIP-16 | PDIP-16 | PDIP-16 |
| Pin Count | 16 pins | 16 pins | 16 pins |
| Device Function | 8-bit I/O expander | 8-bit I/O expander | 8-bit I/O expander |
| Quantity-1 Price | Unverified as of 2026-10-29 | Unverified as of 2026-10-29 | Unverified as of 2026-10-29 |
主な差別化要因
- Closest identified same-package alternative （vs PCF8574P)
- Direct 8-bit I/O expansion footprint option （vs PCA9536DR)
- Same-family A-series alternative （vs PCF8574AP)
設計ノート
Do not release the PCB layout until the exact PCF8574AN package drawing and pin names have been obtained from the Texas Instruments datasheet. Verify that the footprint matches the 16-pin DIP lead pitch, row spacing, and pin-1 orientation. If the PCB may later use the PCF8574P or PCF8574AP, check whether their reset and electrical behavior is identical; a shared footprint reduces assembly options but does not by itself prove functional interchangeability.
Route the serial clock and data as a short, matched pair on a quiet section of the board, and place any required pull-up resistors at the bus endpoint according to the verified operating voltage and bus capacitance. The supplied data does not specify the maximum clock frequency or logic thresholds, so calculate the bus timing margin from the actual host controller and peripheral datasheets. Avoid long stubs, unnecessary test pads, and switching-regulator or clock nodes beneath the bus traces.
Place the manufacturer's required input and bypass capacitors adjacent to their assigned package pins and account for startup current when all eight outputs change state. Because the verified dataset omits supply voltage, quiescent current, output-drive limits, and absolute maximum ratings, do not select capacitor voltage, regulator headroom, or external load current from generic assumptions. Validate the worst-case supply droop and digital-load transitions in the assembled board.
コンプライアンス情報
The supplied verified dataset did not include a manufacturer declaration, datasheet, or distributor product record. Compliance and environmental claims therefore remain unknown. AEC-Q100 is marked not applicable because PCF8574AN was not identified as an automotive-qualified device in the provided data.