TCA9554ADBQR

The TCA9554ADBQR is an 8-bit I2C I/O expander (GPIO) from NXP’s TCA9554A family. It lets a microcontroller add eight general-purpose pins via the I2C bus.
Key points:
- 8 I/O pins that can be configured as input or output
- I2C interface (up to 400 kHz); 7-bit address derived from A0–A2 (up to 8 devices on the bus)
- Registers for I/O direction, output state, input state, and optional polarity inversion
- Interrupt output (INT) for alerting the host when inputs change
- Low power consumption; operating voltage typically 1.65–5.5 V (check datasheet for exact range)
- Package variant “DBQR” indicates a specific RoHS-compliant package variant
Typical use:
- Expand MCU GPIOs for LEDs, buttons, or sensors
- Read inputs and drive outputs with simple I2C commands
- Configure interrupt for event-driven tasks
For exact electrical specs, pinout, and address map, refer to the TCA9554A datasheet.

Common equivalents to TI TCA9554A (TCA9554ADBQR) include:
- NXP PCA9554A / PCAL9554A (direct-compatible)
- TI TCA6408A (similar 8-bit I2C GPIO expander)
- Microchip MCP23008 (8-bit I2C GPIO expander)
- NXP PCF8574 / PCF8574A (similar but quasi‑bidirectional)
Verify register maps, polarity/configuration and interrupt behavior in datasheets before substituting.

Here are the typical features of the TCA9554ADBQR:
- I2C-bus 8-bit GPIO expander: provides 8 programmable I/O lines.
- Programmable I/O directions: per-pin control via IODIR and a GPIO data register for read/write.
- Optional features: input pull-ups (GPPU) and input polarity inversion (IPOL).
- Interrupt output: INT pin signals changes on input pins.
- Addressability: A0–A2 pins allow up to 8 devices on the same I2C bus.
- Supply and speed: operating voltage from about 1.65 V to 5.5 V; supports standard (100 kHz) and fast-mode (400 kHz) I2C.
- Power-on reset and low-power operation.
- Package/qualification: available in RoHS-compliant packaging suitable for embedded applications (ADBQR variant).

Pin count: 16 pins.
Functions (typical pin list):
- P0–P7: Eight quasi‑bidirectional general-purpose I/O pins (programmable input/output via I²C).
- SDA, SCL: I²C data and clock lines.
- A0, A1, A2: Hardware address inputs (set the device I²C address).
- INT: Open‑drain, active‑low interrupt output (signals input changes/conditions).
- VCC: Power supply.
- GND: Ground.
(The TCA9554A is an I²C 8‑bit I/O expander—use I²C registers to configure/read/write the P pins; INT is open‑drain and requires a pull‑up.)

Manufacturer: Texas Instruments (TI).
What kind of company: Texas Instruments Incorporated is an American semiconductor company that designs and manufactures analog and embedded processing integrated circuits and related electronic components (ICs). TI is a global electronics/semiconductor supplier serving industrial, automotive, consumer, and communications markets; it also provides development tools, reference designs and technical support.

TCA9554ADBQR is an 8-bit I2C I/O expander. Applications include:
- I2C I/O expansion for microcontrollers (add 8 GPIOs)
- Driving LEDs and reading switches/sensors
- Keyboard/sensor interfaces (simple matrix or single-ended I/O)
- Embedded control in home automation and consumer electronics
- Industrial automation and remote I/O expansion
- Robotics and hobby projects needing extra GPIOs without MCU pin clutter

The TCA9554ADBQR is supplied in a 14-pin VSSOP (DBQ) package and comes on tape-and-reel (R suffix).