TCA9555DBT - 16-Bit I/O Expander | Texas Instruments
部品番号: TCA9555DBT ✓ 生産中TCA9555DBT 概要
An I/O expander is an interface IC that increases the number of digital input and output pins available to a host controller. It connects through a two-wire I2C or SMBus interface and reduces the number of general-purpose pins required on a microcontroller, processor, or programmable logic device. The TCA9555 belongs to the interface-controller hierarchy, where I2C/SMBus expansion reduces interconnect complexity while preserving digital control over attached peripherals.
The TCA9555 provides 16 I/O lines, an interrupt output, configuration registers, and weak pull-up capability. According to the Texas Instruments product page, it operates from 1.65 V to 5.5 V and supports I2C/SMBus communication at up to 400 kHz. Its configurable I/O architecture allows a system designer to group external lines into input, output, or mixed operating arrangements and to read their states through the serial interface.
The interrupt output provides a hardware indication that a change has occurred on an input, allowing the connected controller to respond without continuous polling. Configuration registers define the direction of each I/O line, while the optional weak pull-ups can support open-drain-style bus arrangements when external pull-ups are not present. These features make the device useful when a design needs more control lines than the host device can expose directly.
Typical uses include low-voltage embedded control, display interfaces, key matrices, relay and sensor interfaces, and general-purpose I/O expansion. The 1.65 V minimum supply voltage also supports systems operating below conventional 3.3 V and 5 V logic levels, although every connected I2C device must use a compatible voltage range and the I/O levels must be checked against the system requirements.
For implementation, connect the supply and ground pins to the same appropriate voltage domain, route the I2C clock and data lines to the host bus, and place pull-up resistors where the bus requires them. Use the configuration registers to establish input or output direction before driving an output. Treat the weak pull-ups as a limited auxiliary feature rather than a substitute for correctly sized external bus pull-ups.
This page consolidates the device's principal interface, voltage, frequency, addressing, and package characteristics with engineering guidance for layout, firmware, and component selection. It also distinguishes verified drop-in replacements from devices that merely perform a similar function, helping engineers preserve footprint and pin compatibility during sourcing and design reviews.
ドロップイン代替品: TCA9555DBT — 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TCA9555DBT 仕様
| Product Type | 16-bit I/O expander |
| Number of I/O Lines | 16 lines |
| Supply Voltage Range | 1.65 V to 5.5 V |
| Bus Interface | I2C and SMBus |
| Maximum Bus Frequency | 400 kHz |
| Interrupt Output | Yes |
| Configuration Registers | Yes |
| Weak Pull-Ups | Yes |
| Programmable Addresses | 8 addresses |
| パッケージ | 24-pin SSOP |
| 実装タイプ | Surface mount |
| ピン数 | 24 pins |
TCA9555DBT 24-pin ssop ピン配置ガイド
TCA9555DBT (24-pin ssop 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: TCA9555DBT.
詳細は データシート をご参照ください。
主な用途
TCA9555DBT の用途: 6 件s: Embedded Control I/O Expansion, Display and Interface Control, Key Matrix and Human Interface Control, Industrial Sensor and Relay Interface, Battery-Powered Portable Equipment, Server and Networking Peripheral Control.
Embedded Control I/O Expansion
The TCA9555DBT fits embedded control designs that need more digital lines than the host microcontroller can expose directly. Its 16 I/O lines are configured through dedicated registers and accessed over I2C or SMBus at up to 400 kHz, while the operating range of 1.65 V to 5.5 V supports low-voltage systems. Place the expander between the host and external logic, configure each line as input or output during initialization, and use the interrupt output to identify input changes without continuous bus polling.
おすすめ
Display and Interface Control
The TCA9555DBT can add control signals for display modules, status indicators, or other interface logic without assigning every line to the main processor. Sixteen configurable I/O lines provide more routing flexibility than a small dedicated expander, and the interrupt output can notify the controller of an external status change. Operating from 1.65 V to 5.5 V supports both low-voltage and conventional logic systems, although the host, expander, and attached peripherals must share compatible voltage levels.
おすすめ
Key Matrix and Human Interface Control
A TCA9555DBT is well suited to key matrices, panel switches, and other human-interface lines because 16 digital I/O channels can be organized as inputs and outputs within one device. The 400 kHz I2C/SMBus interface allows the controller to scan or read the connected lines efficiently, and the interrupt output provides a hardware indication of a state change. Configure the direction registers before use and account for the device's weak-pull-up option when designing the external line network.
おすすめ
Industrial Sensor and Relay Interface
The TCA9555DBT can bridge a low-voltage controller to sensor status inputs and relay-control outputs in industrial equipment. Sixteen configurable lines allow several external channels to share one I2C/SMBus connection, reducing host pin usage and wiring complexity. The interrupt output helps the controller respond to asynchronous sensor events, while the 1.65 V to 5.5 V supply range supports mixed low-voltage logic designs. Appropriate isolation, protection, and drive-current checks remain necessary for the attached loads.
おすすめ
Battery-Powered Portable Equipment
The TCA9555DBT is suitable for portable and battery-powered equipment that operates at low logic voltages and needs additional digital control. Its supply range starts at 1.65 V, and the I2C/SMBus interface operates up to 400 kHz, allowing the host processor to share a two-wire bus with the expander. Sixteen I/O lines can monitor switches or drive low-current indicators while the interrupt output reduces the need for regular polling. Power-budget calculations should include both the expander and the loads connected to its output lines.
おすすめ
Server and Networking Peripheral Control
The TCA9555DBT can consolidate miscellaneous control and status signals in server, networking, or communications equipment. A single I2C/SMBus connection provides access to 16 configurable lines, supporting indicators, fault signals, configuration straps, or peripheral enables. The interrupt output can alert the controller when a monitored input changes, while the 400 kHz bus capability supports efficient serial access. The selected 24-pin SSOP footprint requires careful routing, and signal levels must remain compatible with the rest of the control subsystem.
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: TCA9555DBT — 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 |
|---|---|
| Package | 24-pin SSOP |
| Brand | Texas Instruments |
| Number of I/O Lines | 16 lines |
| Supply Voltage Range | 1.65 V to 5.5 V |
| Bus Interface | I2C and SMBus |
| Maximum Bus Frequency | 400 kHz |
| Interrupt Output | Yes |
| Configuration Registers | Yes |
| Weak Pull-Ups | Yes |
| Programmable Addresses | 8 addresses |
主な差別化要因
- Supports low-voltage operation extending to 1.65 V （vs TCA9555PWR)
- Provides 16 configurable lines with interrupt support （vs PCA9554PWR)
- Eight selectable bus addresses support multiple expanders （vs PCA9534PWR)
設計ノート
Connect VCC and ground to the same voltage domain as the intended I2C system, and verify that every external signal remains within the device's specified input and output limits. The TCA9555DBT operates from 1.65 V to 5.5 V, but the interface host and attached peripherals must also be compatible with that voltage. Use the configuration registers to establish input or output direction before writing an output level, and include the connected load current in the system power budget.
Place the TCA9555DBT near the connector, relay, sensor, or control signals it serves to keep PCB traces short and improve signal behavior. Route the I2C clock and data lines as a compact two-wire bus, provide the required pull-up network, and keep the route away from high-slew-rate switching nodes where practical. Because the verified ordering information identifies a 24-pin SSOP but does not supply numbered pin assignments, use the manufacturer pin table before creating the footprint and tracks.
Do not treat the integrated weak pull-ups as a complete substitute for correctly selected external I2C bus pull-ups. Confirm the bus voltage, pull-up resistance, total bus capacitance, and the maximum 400 kHz operating condition in the complete circuit. Also avoid assigning the same I2C address to multiple expanders: the device supports eight addresses, but address pins must still be planned so every expander on the shared bus has a unique configuration.
Use the interrupt output as an event-driven signal rather than polling every I/O line continuously. Debounce the physical source of an interrupt in hardware or firmware, configure the relevant input direction before arming the interrupt function, and confirm whether the line should remain latched until acknowledged. This arrangement can reduce unnecessary I2C/SMBus traffic and system activity when only a small subset of the 16 digital lines changes frequently.
コンプライアンス情報
The available product and ordering information does not state the RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. The device is an interface IC rather than an automotive-qualified power component, so AEC-Q100 is not applicable.