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Texas Instruments PCA9554DB
- Part No.:
- PCA9554DB
- Manufacturer:
- Texas Instruments
- Category:
- I/O Expanders
- Package:
- 16-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
PCA9554DB.pdf
- Description:
- IC XPNDR 400KHZ I2C SMBUS 16SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,606
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Product details
Overview
PCA9554DB from Texas Instruments is an 8-bit I²C/SMBus remote I/O expander with interrupt output, configuration registers, and 5-V-tolerant I/Os. It operates from 2.3 V to 5.5 V, supports 400-kHz Fast Mode I²C, and features latched outputs with 25 mA sink capability per port for direct LED driving. Used in microcontroller-based systems requiring scalable GPIO expansion with change-of-state notification.
For engineers reviewing the PCA9554DB datasheet, PCA9554DB pinout, PCA9554DB application, or PCA9554DB equivalent, this page delivers verified technical context, package-specific pin mapping (SSOP-16), real-world use cases, and two validated alternative parts - all grounded in TI's SCPS128D production datasheet (Rev D, March 2021).
Technical Context
The PCA9554DB implements a register-mapped I²C slave interface with four dedicated 8-bit registers: Configuration (I/O direction), Input, Output, and Polarity Inversion. Its internal power-on reset initializes all I/Os as high-impedance inputs with weak pullups, eliminating glitches at startup.
Interrupt generation is edge-triggered on input state changes relative to the Input Port register; the open-drain INT output requires an external pullup and resets upon reading the corresponding input register. Hardware address pins A0–A2 support up to eight devices on one bus, and all I/Os tolerate 5-V signals while operating down to 2.3 V VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Speed | 400 kHz Fast Mode - enables high-throughput GPIO control without slowing system bus. |
| VCC Range | 2.3 V to 5.5 V - interoperates across 2.5 V, 3.3 V, and 5 V logic domains. |
| I/O Sink Current | 25 mA per port (P0–P7) - sufficient to drive LEDs directly without external drivers. |
| Interrupt Latency | 4 µs max tiv - ensures rapid notification of input transitions to host MCU. |
| ESD Robustness | 2000-V HBM - meets industrial-grade reliability requirements per JESD22-A114. |
| Power-On Reset | VPORR = 1.2–1.5 V - guarantees deterministic initialization before firmware execution. |
| Input Tolerance | 5-V tolerant I/Os - allows interfacing with higher-voltage peripherals while powered from lower VCC. |
Pinout & Package
PCA9554DB is supplied in a 16-pin SSOP (Shrink Small Outline Package) with nominal body size 6.20 mm × 5.30 mm. Pin functions are electrically identical across DB, DBQ, DGV, DW, and PW packages per TI SCPS128D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A2 | Hardware I²C address select | Three binary inputs set fixed 7-bit slave address (0x20–0x27); no software configuration needed. |
| P0–P7 | Configurable I/O port | Bi-directional, latched, push-pull ports - each independently set as input or output via Configuration register. |
| GND | Ground reference | Primary return path for VCC and I/O currents; must be low-impedance for noise immunity. |
| VCC | Supply voltage | 2.3–5.5 V power rail; powers internal logic and I/O buffers; decoupling capacitor required. |
| SDA | I²C serial data | Open-drain bidirectional line; requires external pullup resistor (typically 2.2–10 kΩ to VCC). |
| SCL | I²C serial clock | Open-drain input; master-generated clock; requires external pullup resistor. |
| INT | Interrupt output | Active-low, open-drain signal asserted when any P-port input state differs from Input Port register. |
Key Features
| Feature | Design Value |
|---|---|
| Input/Output Configuration Register | Enables per-pin direction control (input/output) without hardware rework - supports dynamic GPIO reassignment in firmware. |
| Polarity Inversion Register | Flips logical sense of input reads (active-high ↔ active-low) - eliminates external inverters for switch or sensor interfaces. |
| Internal Power-On Reset | Guarantees known register state (all I/Os = inputs, weak pullups enabled) at power-up - removes need for host-initiated reset sequence. |
| No Glitch On Power Up | Prevents spurious output transitions during VCC ramp - critical for driving relays, solenoids, or LEDs in safety-aware systems. |
| Latched Outputs with High-Current Drive | 25 mA sink per port supports direct LED drive with single-resistor current limiting - reduces BOM count and PCB area. |
Applications
| Industrial Control Panel | Smart Home Hub |
|---|---|
Use Scenario: Remote monitoring of 8 mechanical pushbuttons and status LEDs on a DIN-rail mounted PLC I/O module. IC Role / Device Role / Timing Role: I/O expander providing interrupt-driven input sampling and LED output control over shared I²C bus with main controller. Use Value: Reduces host MCU GPIO usage by 8 pins; INT signal eliminates polling overhead and lowers system power consumption. | Use Scenario: Central hub managing door/window sensors (dry contacts), motion detectors, and RGB LED indicators across multiple rooms. IC Role / Device Role / Timing Role: Remote sensor interface and actuator driver with change-of-state interrupt reporting to ARM Cortex-M host. Use Value: Enables sub-100 µs response to security events via hardware interrupt - faster than periodic I²C polling at 100 Hz. |
| Medical Device Front Panel | Automotive Body Controller |
Use Scenario: Keypad and status indicator interface on a portable diagnostic instrument with strict ESD and reliability requirements. IC Role / Device Role / Timing Role: ESD-hardened GPIO extender handling tactile button inputs and bi-color LED feedback under 2.5 V–3.3 V operation. Use Value: 2000-V HBM rating meets IEC 61000-4-2 Level 4; 5-V-tolerant inputs simplify integration with legacy panel components. | Use Scenario: Interior lighting control module managing 8 individual LED strips (map lights, footwell, dome) in a vehicle cabin. IC Role / Device Role / Timing Role: I²C-connected LED driver with programmable polarity and latch retention during bus arbitration delays. Use Value: Latched outputs prevent LED flicker during I²C contention; 25 mA sink per channel eliminates need for discrete MOSFETs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C I/O expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9554PW | Identical electrical specs and register map; TSSOP-16 package (5.00 mm × 4.40 mm), slightly larger footprint than SSOP-16. | Same interrupt behavior, I²C timing, and software compatibility - suitable for designs where thermal resistance (RθJA = 63.2°C/W) is less critical than board space. | Select PCA9554PW if TSSOP assembly infrastructure is preferred or if marginally higher junction-to-ambient thermal resistance is acceptable. |
| PCA9538DB | 8-bit I²C expander with identical SSOP-16 pinout but lacks polarity inversion register and has lower IOL (10 mA vs 25 mA). | Cannot drive standard LEDs directly without external drivers; missing polarity inversion increases firmware complexity for active-low sensors. | Choose PCA9538DB only when cost is primary constraint and reduced drive strength/polarity flexibility is acceptable. |
Compared with PCA9554PW, PCA9554DB offers tighter thermal performance (RθJA = 113.2°C/W) in a smaller SSOP footprint; versus PCA9538DB, it adds critical polarity inversion and 2.5× higher output sink current - enabling simpler, more robust embedded I/O designs.
Availability
PCA9554DB is available at Aetrix Electronics and suitable for industrial control panels, smart home hubs, medical front panels, and automotive body controllers requiring stable component supply and long-term manufacturability.
Supply support for PCA9554DB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor leader delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.
The PCA9554 product line targets I²C-based remote I/O expansion in resource-constrained embedded systems - designed specifically for deterministic interrupt response, low-power standby operation, and seamless integration with 8-/16-/32-bit microcontrollers.
FAQ
What is the maximum I²C clock frequency supported by the PCA9554DB?
The PCA9554DB supports Fast Mode I²C operation up to 400 kHz, as confirmed in Section 6.6 of the TI SCPS128D datasheet. This allows efficient register access and data transfer without compromising bus timing margins in multi-slave systems. The PCA9554DB maintains full functionality across its entire 2.3 V–5.5 V VCC range at this speed.
Does the PCA9554DB require external pullup resistors on SDA and SCL lines?
Yes, the PCA9554DB requires external pullup resistors on both SDA and SCL lines because it uses open-drain outputs for these I²C bus signals. Typical values range from 2.2 kΩ to 10 kΩ to VCC, selected based on bus capacitance and desired rise time. The INT pin also requires a pullup resistor for proper interrupt signaling.
Can the PCA9554DB drive standard LEDs directly without additional components?
Yes, the PCA9554DB can drive standard LEDs directly: each P-port (P0–P7) provides up to 25 mA sink current at VOL ≤ 0.5 V (VCC = 3 V), sufficient for common 2–20 mA indicator LEDs. A single series current-limiting resistor per LED is required; no external transistors or drivers are needed for basic illumination tasks.
How does the interrupt (INT) output of the PCA9554DB behave during I²C read operations?
The PCA9554DB INT output de-asserts automatically after reading the Input Port register that triggered the interrupt - specifically on the ACK/NACK bit following the rising edge of SCL. However, an errata (Section 8.2.3.1) notes INT may improperly de-assert if the last command byte written was 00h; workaround requires writing a non-zero register pointer before subsequent reads.
Is the PCA9554DB pin-compatible with the PCF8574?
The PCA9554DB is pin-to-pin and I²C address compatible with the PCF8574 per Section 4 of the datasheet, allowing direct PCB replacement. However, software changes are required due to enhanced register architecture (Configuration, Polarity Inversion) and interrupt functionality - the PCA9554DB is not a drop-in firmware replacement.
PCA9554DB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-SSOP (0.209", 5.30mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- I2C, SMBus
- Interrupt Output:
- Yes
- Features:
- POR
- Output Type:
- Push-Pull
- Current - Output Source/Sink:
- 10mA, 25mA
- Clock Frequency:
- 400 kHz
- Voltage - Supply:
- 2.3V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SSOP
PCA9554DB FAQ
1.How can I place an order for PCA9554DB through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9554DB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PCA9554DB reliable?
The price and inventory of PCA9554DB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9554DB is usually 5 days.
3.What payment methods are accepted for PCA9554DB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9554DB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9554DB?
PCA9554DB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9554DB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PCA9554DB?
For technical support, including PCA9554DB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9554DB requirements.
6.How does Aetrix verify that PCA9554DB is sourced from the original manufacturer or authorized distributors?
All PCA9554DB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PCA9554DB meets industry standards.
7.What is the process for return or replacement of PCA9554DB?
All PCA9554DB units undergo pre-shipment inspection (PSI). If there is an issue with PCA9554DB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PCA9554DB part is unused and in its original packaging.
Return procedure for PCA9554DB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
PCA9554DB Tags
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