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NXP Semiconductors PCA9555DB,112
- Part No.:
- PCA9555DB,112
- Manufacturer:
- NXP Semiconductors
- Category:
- I/O Expanders
- Package:
- 24-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
PCA9555DB,112.pdf
- Description:
- IC XPNDR 400KHZ I2C SMBUS 24SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,607
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Product details
Overview
PCA9555DB,112 from NXP Semiconductors is a 16-bit I²C-bus/SMBus GPIO expander in SSOP24 package, providing configurable parallel I/O for embedded control systems. It features 5 V-tolerant I/Os, active-low open-drain interrupt output, polarity inversion registers, and operates from 2.3 V to 5.5 V supply. It is used in industrial HMI panels to extend microcontroller I/O for keypad scanning and LED status indication.
For engineers reviewing the PCA9555DB,112 datasheet, PCA9555DB,112 pinout, PCA9555DB,112 application, or PCA9555DB,112 equivalent, key selection criteria include I²C address configurability (A0–A2), interrupt-driven input change detection, 16-bit port register independence, and 5 V I/O tolerance in space-constrained SSOP packaging.
Technical Context
The PCA9555DB,112 implements two independent 8-bit I/O ports (Port 0 and Port 1), each with dedicated configuration, input, output, and polarity inversion registers. Its I²C interface supports standard (100 kHz) and fast-mode (400 kHz) clock rates, with noise filtering on SCL/SDA inputs and internal power-on reset.
Each I/O defaults to high-impedance input with weak pull-up to VDD at power-up; direction is software-configurable per pin via Configuration Registers 6 and 7. The open-drain INT output asserts when any configured input changes state relative to its Input Port register value - and clears only upon reading the corresponding port register.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I/O Count | 16 bidirectional pins (8 per port), individually configurable as input or output |
| Supply Voltage | 2.3 V to 5.5 V - enables direct interfacing with 3.3 V and 5 V logic domains |
| I/O Voltage Tolerance | 5 V tolerant - allows safe connection to 5 V peripherals even when VDD = 3.3 V |
| I²C Clock Rate | 0 Hz to 400 kHz - supports fast-mode SMBus communication without timing constraints |
| Interrupt Output | Active-low open-drain INT - signals input state change and requires external pull-up |
| Operating Temperature | −40 °C to +85 °C - qualified for industrial ambient environments |
| ESD Protection | 2000 V HBM - meets JEDEC JESD22-A114 for robust handling in manufacturing |
Pinout & Package
PCA9555DB,112 uses the SSOP24 (SOT340-1) package: plastic shrink small outline, 24 leads, 5.3 mm body width, surface-mount compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| INT (Pin 1) | Interrupt output | Open-drain signal asserting low when input state differs from Input Port register |
| A1 (Pin 2), A2 (Pin 3), A0 (Pin 21) | I²C address inputs | Set 3-bit slave address; enable up to eight devices on same bus (0x20–0x27) |
| IO0_0–IO0_7 (Pins 4–11) | Port 0 I/O | Eight bidirectional pins with independent configuration, polarity, and data registers |
| VSS (Pin 12) | Ground | Primary supply return; must be connected for proper operation |
| IO1_0–IO1_7 (Pins 13–20) | Port 1 I/O | Second 8-bit port with identical register architecture and independent read/write access |
| SCL (Pin 22), SDA (Pin 23) | I²C bus interface | Serial clock and bidirectional data lines with integrated noise filters |
| VDD (Pin 24) | Power supply | 2.3 V–5.5 V core and I/O supply; powers internal logic and weak pull-ups |
Key Features
| Feature | Design Value |
|---|---|
| Polarity Inversion Register | Per-port 8-bit register flips read-back logic level of inputs - simplifies firmware handling of active-low sensors |
| Individual I/O Configuration | Each of 16 pins independently set as input or output via dedicated Configuration Registers - eliminates fixed-direction port limitations |
| No Glitch on Power-Up | Internal power-on reset ensures all registers initialize to known states before I²C communication begins |
| Low Standby Current | 0.25 µA typical at VDD = 5.5 V with all I/Os as inputs - critical for battery-backed systems |
| 5 V-Tolerant I/Os | Accepts up to 5.5 V on I/O pins regardless of VDD voltage - enables mixed-voltage system integration |
Applications
| Industrial Keypad Interface | LED Status Panel Control |
|---|---|
Use Scenario: Scanning 10-digit numeric keypad in factory HMI panel with limited MCU GPIO. IC Role / Device Role / Timing Role: GPIO expander providing 16 programmable I/Os; Port 0 scans rows, Port 1 reads columns; INT signals keypress event. Use Value: Reduces host MCU polling overhead by 100% via interrupt-driven detection and eliminates need for external shift registers or multiplexers. | Use Scenario: Driving 12 bi-color LEDs for machine status (RUN/ALARM/FAULT) in PLC backplane module. IC Role / Device Role / Timing Role: Output port driver with configurable polarity; outputs sourced/sunk under I²C command; no timing-critical software bit-banging required. Use Value: Enables dynamic LED state updates via single I²C write to Output Port registers - reduces firmware complexity and CPU load. |
| ACPI Power Switch Monitoring | Fan Speed Feedback Interface |
Use Scenario: Monitoring mechanical power switch state and thermal shutdown signals in server power management unit. IC Role / Device Role / Timing Role: Input monitor with interrupt-on-change; configured as 8-input port with pull-ups; INT triggers host response within 100 µs of switch closure. Use Value: Guarantees immediate host awareness of power events without continuous polling - improves system responsiveness and energy efficiency. | Use Scenario: Reading tachometer pulses from four 4-wire cooling fans in telecom chassis. IC Role / Device Role / Timing Role: High-impedance input capture port; fan pulse edges detected via INT assertion; Input Port registers sampled on interrupt service. Use Value: Supports accurate RPM calculation using hardware-triggered sampling - avoids timer resource contention and jitter in main application thread. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar GPIO expansion applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9554DB,112 | 8-bit I/O count; identical SSOP24 package and I²C address map; no polarity inversion register | Limited to simpler systems requiring ≤8 expandable I/Os; lacks input polarity flexibility | Select when pin count and BOM cost are prioritized over feature richness and future scalability |
| TCA6424ARGJR | 24-pin VQFN package; 24 I/Os; supports 1.65 V–5.5 V; includes glitch filter per I/O and programmable push-pull/open-drain output | Better suited for ultra-low-voltage designs and noise-prone environments; higher pin density but different footprint | Choose for new designs needing >16 I/Os, lower VDD support, or enhanced EMI resilience - requires PCB redesign |
Compared with PCA9554DB,112, PCA9555DB,112 delivers double I/O count and polarity inversion for sensor compatibility; versus TCA6424ARGJR, it offers proven industrial qualification and identical I²C register mapping but lacks per-pin filtering and push-pull output mode.
Availability
PCA9555DB,112 is available at Aetrix Electronics and suitable for industrial HMIs, PLC I/O modules, server power management units, and telecom chassis requiring stable component supply across extended product lifecycles.
Supply support for PCA9555DB,112 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
NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.
The PCA9555 product line delivers scalable I²C-based GPIO expansion targeting resource-constrained embedded controllers in industrial automation and infrastructure equipment.
FAQ
What is the default I/O configuration of PCA9555DB,112 at power-up?
At power-on reset, all 16 I/O pins of PCA9555DB,112 default to high-impedance inputs with internal weak pull-ups to VDD. Configuration registers (6 and 7) initialize to 0xFF, and Input Port registers reflect externally applied logic levels. This ensures safe, non-driving behavior before firmware initialization.
How does the interrupt output (INT) of PCA9555DB,112 behave during I/O reconfiguration?
The INT output of PCA9555DB,112 may assert a false interrupt if an I/O pin is changed from output to input while its external voltage level differs from the stored value in the corresponding Input Port register. To avoid this, ensure the pin's external state matches the Input Port register before switching direction - or clear INT by reading the affected port after reconfiguration.
Can PCA9555DB,112 drive LEDs directly, and what current limits apply?
Yes, PCA9555DB,112 can sink or source current to drive LEDs directly. Each I/O supports up to 25 mA, with maximum 100 mA per 8-bit port and 200 mA total device limit. For reliable operation, external current-limiting resistors must be used, and total sourced current must not exceed 160 mA per datasheet specification.
What I²C address range does PCA9555DB,112 support, and how is it set?
PCA9555DB,112 supports seven fixed I²C slave addresses (0x20–0x26) determined by the logic states of hardware pins A0, A1, and A2. With all three grounded, the address is 0x20; tying A0 high sets 0x21, and so on. Address 0x27 is reserved and not usable. This allows up to seven PCA9555DB,112 devices on one bus.
Does PCA9555DB,112 require external pull-up resistors on SCL and SDA lines?
Yes, PCA9555DB,112 requires external pull-up resistors on both SCL and SDA lines, as specified by I²C bus standards. Typical values range from 1.8 kΩ to 10 kΩ depending on bus capacitance and speed; 4.7 kΩ is commonly used for 400 kHz operation. The device itself does not integrate pull-ups on these lines.
PCA9555DB,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 24-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Number of I/O:
- 16
- 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:
- 24-SSOP
PCA9555DB,112 FAQ
1.How can I place an order for PCA9555DB,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9555DB,112 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 PCA9555DB,112 reliable?
The price and inventory of PCA9555DB,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9555DB,112 is usually 5 days.
3.What payment methods are accepted for PCA9555DB,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9555DB,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9555DB,112?
PCA9555DB,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9555DB,112 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 PCA9555DB,112?
For technical support, including PCA9555DB,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9555DB,112 requirements.
6.How does Aetrix verify that PCA9555DB,112 is sourced from the original manufacturer or authorized distributors?
All PCA9555DB,112 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 PCA9555DB,112 meets industry standards.
7.What is the process for return or replacement of PCA9555DB,112?
All PCA9555DB,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9555DB,112, 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 PCA9555DB,112 part is unused and in its original packaging.
Return procedure for PCA9555DB,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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