TCA9555DBT - 16-Bit I/O Expander | Texas Instruments
料号： TCA9555DBT ✓ 量产中TCA9555DBT 概述
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.
直接替换替代料： TCA9555DBT ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
该产品暂无直接替换替代料。
请求替代料TCA9555DBT 规格参数
| 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 |
| 封装 | 24-pin SSOP |
| 安装类型 | Surface mount |
| 引脚数 | 24 pins |
TCA9555DBT 24-pin ssop 引脚配置指南
TCA9555DBT（24-pin ssop 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： TCA9555DBT.
请参阅 数据手册 以查看完整引脚配置。
典型应用
TCA9555DBT 适用于 6 应用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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
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.
推荐
推荐产品汇总
工程参考数据： TCA9555DBT ——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 |
|---|---|
| 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 |
关键差异点
- Supports low-voltage operation extending to 1.65 V （对比 TCA9555PWR)
- Provides 16 configurable lines with interrupt support （对比 PCA9554PWR)
- Eight selectable bus addresses support multiple expanders （对比 PCA9534PWR)
设计说明
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.
合规信息
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.