TCA9554DWR - 8-Bit I2C I/O Expander | Texas Instruments
Référence : TCA9554DWR ✓ ActifTCA9554DWR Présentation
An I/O expander is an interface IC that increases the number of general-purpose inputs and outputs available to an embedded controller. It belongs to the I/O expander category, within interface ICs and the broader semiconductor hierarchy. Instead of dedicating eight microcontroller pins to switches, LEDs, keypads, or status signals, the TCA9554DWR connects these external circuits through a two-wire serial bus while retaining eight host-side I/O lines.
The device provides hardware-selectable addresses through the A0, A1, and A2 pins, allowing as many as eight devices to operate on one I2C bus. Its interrupt feature provides a hardware signal when an input state changes, allowing a microcontroller to remain in a low-power state until an external event requires attention. Configurable ports can operate as inputs or outputs, and the device includes weak pull-ups for inputs.
The TCA9554DWR uses the I2C/SMBus serial interface at up to 400 kHz. Address selection, power-on reset behavior, configuration registers, and interrupt handling make it useful where several low-speed peripheral lines must be consolidated. The wide 1.65 V to 5.5 V operating range accommodates both low-voltage and conventional 5 V systems, subject to the voltage limits of connected peripherals.
Typical applications include LED status and keypad interfaces, configuration controls in embedded equipment, alarm and sensor signaling, and general-purpose I/O expansion in industrial, consumer, and communications products. The interrupt output can reduce polling activity, while address selection permits multiple expanders when a board requires more than eight additional lines.
PCB implementation should preserve short I2C traces, provide the decoupling required by the manufacturer guidance, and route the open-drain interrupt appropriately. External pull-ups may be required on I2C lines or interrupt outputs when the onboard weak pull-ups are insufficient for the bus capacitance, speed, or required sink current.
This page summarizes the manufacturer specifications, practical interface guidance, verified drop-in considerations, and application trade-offs. It is intended to help engineers compare bus topology, addressing, voltage compatibility, and package reuse before integrating the TCA9554DWR into a new design.
Alternatives de remplacement direct pour TCA9554DWR — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec TCA9554DWR (même facteur de forme et même empreinte) — différant par Configuration Registers, Interrupt Output.
TCA9554DWT
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Voir la fiche technique →TCA9554DWR Spécifications
| Number of I/O Ports | 8 ports |
| I/O Direction | Configurable input or output |
| Type d'interface | I2C/SMBus |
| Operating Supply Voltage Range | 1.65 V to 5.5 V |
| Maximum I2C Clock Frequency | 400 kHz |
| Hardware Address Inputs | 3 inputs, A0/A1/A2 |
| Maximum Devices per I2C Bus | 8 devices |
| Interrupt Output | 1 open-drain interrupt output |
| Configuration Registers | 8-bit input and output configuration registers |
| Input Pull-Up Capability | Weak pull-ups |
| Boîtier | 16-pin SOIC |
| Type de montage | Surface mount |
| Power-On Reset | Device returns to default state when supply voltage is cycled |
| Statut RoHS | unknown |
| REACH Status | unknown |
Guide de configuration des broches du TCA9554DWR 16-pin soic
Configuration des broches du TCA9554DWR (boîtier 16-pin soic). La numérotation des broches, les fonctions et les schémas de connexion sont définis dans la fiche technique du fabricant. Consultez-la pour l'empreinte exacte et les directives de soudage.
Aucune donnée de brochage détaillée disponible pour TCA9554DWR.
Consultez la fiche technique pour la configuration complète des broches.
Applications typiques
TCA9554DWR convient pour 6 applications: Microcontroller GPIO Expansion, LED Status and Indicator Control, Keypad and Human-Interface Control, Industrial Configuration and Control, Sensor and Alarm Signal Interface, Communications and Network Equipment Control.
Microcontroller GPIO Expansion
The TCA9554DWR extends a constrained microcontroller by adding eight configurable ports over an I2C/SMBus connection at up to 400 kHz. This allows the controller to retain pins for clocking, communications, or timing functions while external buttons, status indicators, and discrete controls use the expander. Its 1.65 V to 5.5 V operating range supports low-voltage embedded platforms as well as 5 V systems. The principal design trade-off is the shared serial bus: every port update occupies bus transactions, so the device is best suited to low-speed controls rather than continuous high-bandwidth data transfer.
LED Status and Indicator Control
The TCA9554DWR can drive groups of LEDs or relay-control inputs while reducing the number of direct microcontroller GPIO connections. Eight ports can be configured individually as outputs, and the 1.65 V to 5.5 V supply range accommodates different logic environments. Using the interrupt feature for related input signals also lets the controller react to a change without continuously polling every port. Before finalizing an LED circuit, verify the port's output-current rating, the LED forward current, polarity arrangement, and any required current-limiting resistors against the manufacturer electrical characteristics.
Keypad and Human-Interface Control
The TCA9554DWR fits keypad matrices and compact human-interface panels because eight configurable ports can combine input scanning functions with output-controlled indicator or enable signals. At an I2C rate of up to 400 kHz, the bus supports ordinary low-speed controls while conserving controller pins. The interrupt output can indicate a detected input transition, reducing the need for frequent status-register reads. Matrix scanning still requires careful debounce and ghost-suppression design, and the selected logic levels must match the keypad and indicator circuitry.
Industrial Configuration and Control
The TCA9554DWR can centralize slow configuration commands, fault flags, and equipment-enable signals in an industrial controller while preserving the host processor's limited GPIO resources. Its three address inputs permit up to eight expanders on one I2C bus, creating a scalable method for distributing discrete control lines across a board. The 1.65 V to 5.5 V operating range supports a range of embedded platforms, but industrial deployment requires checking temperature limits, isolation strategy, grounding, and fault behavior. Firmware should also handle bus errors and unexpected port states.
Sensor and Alarm Signal Interface
The TCA9554DWR can collect digital alarm, tamper, presence, or contact-closure signals when the sensors use compatible logic levels. Configurable inputs with weak pull-ups are useful for simple open or contact outputs, while the interrupt line notifies the controller after a transition. This can reduce repeated polling and lower host-processing activity. The implementation must account for debounce, contact bounce, open-drain behavior, and maximum transition rates, and the selected pull-up arrangement must provide a valid inactive logic level for every connected sensor.
Communications and Network Equipment Control
In communications equipment, the TCA9554DWR can manage front-panel indicators, backplane controls, and miscellaneous status inputs while sharing a compact serial interface with other bus devices. Its address-selection pins allow multiple instances when one board contains several groups of controls, and the 400 kHz I2C rate is suitable for ordinary management traffic rather than high-speed payload transfer. System designers should account for bus loading when several peripherals share the bus and use the interrupt output to request controller attention after relevant events.
Données de référence d'ingénierie pour TCA9554DWR — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | TCA9554DWT |
|---|---|---|
| Brand | Texas Instruments | Texas Instruments |
| Package | 16-SOIC | 16-SOIC |
| Number of I/O Ports | 8 ports | 8 ports |
| Operating Supply Voltage Range | 1.65 V to 5.5 V | 1.65 V to 5.5 V |
| Maximum I2C Clock Frequency | 400 kHz | 400 kHz |
| Interface Type | I2C/SMBus | I2C/SMBus |
| Hardware Address Inputs | 3 inputs, A0/A1/A2 | 3 inputs, A0/A1/A2 |
| Interrupt Output | Open-drain interrupt output | Open-drain interrupt output |
| Port Configuration | Independently configurable input or output | Independently configurable input or output |
| Input Pull-Ups | Weak pull-ups | Weak pull-ups |
Principaux différenciateurs
- Eight ports without consuming eight host GPIO pins (vs TCA9554DWT)
- Three hardware address inputs support a larger bus (vs TCA9554DWT)
- Interrupt output reduces the need for continuous polling (vs TCA9554DWT)
Notes de conception
Place the TCA9554DWR close to the connectors or controlled circuits that use its eight ports, and keep the SDA, SCL, and interrupt routes short. Provide local supply decoupling according to the manufacturer layout guidance. Route the exposed requirements for each I/O signal with adequate drive-current and return-path planning rather than treating every port as a low-current logic load.
The 1.65 V to 5.5 V operating range does not mean that every attached peripheral can use the same supply. Confirm port logic thresholds for mixed-voltage systems and select the I2C pull-up voltage accordingly. Account for port leakage, pull-up current, and attached output loads when estimating supply demand; the complete system current must remain within both the expander and regulator limits.
Do not assume the interrupt pin is active-high or actively drives the bus. Texas Instruments describes an interrupt output that requires the correct pull-up arrangement. Firmware should also distinguish an input transition from a level, clear the interrupt condition according to the device register behavior, and avoid assuming that the interrupt remains asserted until the source signal is physically removed.
Use A0, A1, and A2 to assign a unique address on a shared I2C bus and verify the resulting address against the host firmware. External pull-ups may be necessary for operation at 400 kHz or when total bus capacitance is high. Check rise time and fall time at the actual bus voltage rather than relying only on the nominal 400 kHz frequency limit.
Informations de conformité
The manufacturer product page and distributor information do not provide explicit compliance declarations for this ordering option.