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HomeProductsIntegrated Circuits (ICs)Interface - I/O ExpandersPCA9555DBQR
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PCA9555DBQR - Texas Instruments

Manufacturer Part Number
PCA9555DBQR
Manufacturer
Texas Instruments
Allelco Part Number
32D-PCA9555DBQR
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
37,715 pcs available, New & Original
Parts Description
IC XPNDR 400KHZ I2C SMBUS 24SSOP
Package
24-SSOP
Data sheet
PCA9555DBQR.pdf

PCN Obsolescence/ EOL

Mult Dev EOL 28/Mar/2023.pdf

HTML Datasheet

PCA9555.pdf
RoHs Status
ROHS3 Compliant
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Our certification
In stock: 37715
  • Unit Price: $1.827
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
1+ $1.827 $1.83
10+ $1.784 $17.84
30+ $1.756 $52.68
100+ $1.728 $172.80
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

PCA9555DBQR Tech Specifications
Texas Instruments - PCA9555DBQR technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments - PCA9555DBQR

Product Attribute Attribute Value
Manufacturer Texas Instruments
Voltage - Supply 2.3V ~ 5.5V
Supplier Device Package 24-SSOP
Series -
Package / Case 24-SSOP (0.154", 3.90mm Width)
Package Tape & Reel (TR)
Output Type Push-Pull
Operating Temperature -40°C ~ 85°C
Product Attribute Attribute Value
Number of I/O 16
Mounting Type Surface Mount
Interrupt Output Yes
Interface I²C, SMBus
Features POR
Current - Output Source/Sink 10mA, 25mA
Clock Frequency 400 kHz
Base Product Number PCA9555

Environmental & Export Classifications

ATTRIBUTE DESCRIPTION
RoHs Status ROHS3 Compliant
Moisture Sensitivity Level (MSL) 2 (1 Year)
REACH Status REACH Unaffected
ECCN EAR99
HTSUS 8542.39.0001

Parts Introduction

PCA9555DBQR Image
PCA9555DBQR (1)

Manufacturer Part Number

PCA9555DBQR

Manufacturer

Texas Instruments

Introduction

PCA9555DBQR is an integrated circuit for interfacing applications requiring additional I/O lines.

Product Features and Performance

16-bit I/O expander

I2C and SMBus compatible interface

Built-in interrupt output signaling feature

Power-on reset function

Push-pull output style

Supports 400 kHz I2C bus clock frequency

Product Advantages

Expands I/O capabilities for microcontroller based systems

Provides direct interface with most microprocessors

Reduces complexity by offering integrated features

Easy to use and integrate into existing designs

PCA9555DBQR Image
PCA9555DBQR (2)

Key Technical Parameters

Number of I/O: 16

Interface: I2C, SMBus

Interrupt Output: Yes

Features: Power-on reset (POR)

Current - Output Source/Sink: 10mA, 25mA

Clock Frequency: 400 kHz

Voltage - Supply: 2.3V to 5.5V

Operating Temperature: -40°C to 85°C

Quality and Safety Features

Robust operating temperature range for industrial applications

Complies with safety and regulatory standards

Proven reliability from Texas Instruments

Compatibility

Compatible with microcontrollers and processors supporting I2C or SMBus

Suitable for breadboards and prototyping with 24-SSOP package format

Application Areas

Embedded systems

Industrial controls

Server management

Robotics

Home automation systems

Product Lifecycle

Last Time Buy status

Potential replacements or upgrades may be available

Several Key Reasons to Choose This Product

Industry-leading performance and reliability by Texas Instruments

Significant expansion of I/O lines for complex systems

Ease of integration into existing and new designs

Multi-voltage operations suitable for various applications

Strong support and documentation available from Texas Instruments

Frequently Asked Questions(FAQ)

What are the key differences in electrical characteristics between the PCA9555DBQR and the TCA9555DBR when used in a 3.3V I2C-based sensor interface design?
The PCA9555DBQR and TCA9555DBR are both I2C I/O expanders from Texas Instruments, but they differ in critical electrical parameters relevant to system reliability. The PCA9555DBQR supports a supply voltage range of 2.3V to 5.5V with a maximum output sink current of 25mA per pin, while the TCA9555DBR typically operates at a fixed 3.3V supply and may have lower drive capability. For a 3.3V system requiring robust pull-up networks and stable logic transitions, the PCA9555DBQR’s wider voltage tolerance and higher current sourcing/sinking (up to 10mA source, 25mA sink) provide greater flexibility in driving legacy or long-bus sensors without external buffering. Additionally, the PCA9555DBQR includes Power-On Reset (POR) circuitry that ensures predictable initialization, which is essential for systems with multiple power rails or delayed enable sequences.
How does the interrupt functionality of the PCA9555DBQR improve system efficiency in embedded designs compared to polling-based approaches?
The PCA9555DBQR features an active-low interrupt output (INT) that triggers only when any input changes state, significantly reducing CPU overhead compared to continuous polling of GPIO status registers. In a battery-powered IoT node monitoring 16 discrete inputs such as door sensors or button presses, this feature allows the microcontroller to remain in low-power mode until an event occurs—reducing average current consumption by up to 80% in typical applications. The interrupt signal is edge-sensitive and can be configured independently per port via internal registers, enabling precise event detection without software debouncing. This behavior is especially valuable in real-time systems where response latency must be minimized.
What considerations should be made regarding ESD protection when integrating the PCA9555DBQR into a high-reliability industrial control panel exposed to transient surges?
While the PCA9555DBQR itself offers basic latch-up immunity per JESD78, its absolute maximum ratings indicate a human-body model (HBM) ESD rating below 2kV, which may be insufficient for harsh environments. Industrial panels often experience contact discharges exceeding 4kV HBM. Therefore, external protection components—such as TVS diodes on each input line rated for ±6kV HBM or IEC 61000-4-2 Level 4—are strongly recommended. These should be placed close to connector interfaces and connected to a solid ground plane. Without such mitigation, repeated exposure could compromise the integrity of the PCA9555DBQR’s internal ESD structures, leading to latent failures during field operation.
Can the PCA9555DBQR safely drive inductive loads such as relays or solenoid valves directly, and what precautions apply?
The PCA9555DBQR provides up to 25mA sink current per pin, which exceeds typical relay coil requirements (usually 5–20mA). However, driving inductive loads directly poses risks due to back-EMF when switching off. Without flyback protection, voltage spikes exceeding the device’s 5.5V absolute maximum can occur. To safely switch a 5V relay with 70Ω coil resistance, add a reverse-biased diode (e.g., 1N4148) across the load in parallel with the coil. Alternatively, use an external MOSFET driver stage if higher switching frequencies or faster decay times are needed. Direct driving is feasible but requires careful layout and snubber networks to prevent damage over time.
How does the operating temperature range of the PCA9555DBQR affect its suitability for automotive or outdoor deployment scenarios?
The PCA9555DBQR is specified for operation from -40°C to +85°C, aligning with commercial and extended industrial grades but falling short of full AEC-Q100 qualification required for most automotive systems. Outdoor installations may face thermal cycling beyond this window, particularly in northern climates where temperatures can drop below -40°C or exceed 85°C under direct solar load. While the device will likely function within these extremes intermittently, long-term reliability cannot be guaranteed. For mission-critical applications, consider derating operating conditions or selecting a component with broader thermal margins and formal automotive certification.
What impact does bus capacitance have on the maximum achievable I2C clock speed when using the PCA9555DBQR in a multi-drop configuration?
The PCA9555DBQR supports standard-mode (100 kHz) and fast-mode (400 kHz) I2C communication, with the latter limited by total bus capacitance. Fast-mode requires total bus capacitance below 400 pF; exceeding this value forces clock stretching or reduced speed to maintain signal integrity. In a system with three PCA9555DBQR devices plus two 4.7kΩ pull-ups over a 1-meter cable, measured capacitance might reach 600–800 pF. To maintain 400 kHz operation, either reduce pull-up resistor values (e.g., 2.2kΩ), shorten trace lengths, or insert buffer ICs like PCA9615. Failure to address excessive capacitance results in timing violations and intermittent communication errors.
Why might a designer choose the PCA9555DBQR over discrete transistor-based I/O expanders in a space-constrained PCB layout?
The PCA9555DBQR integrates 16 bidirectional I/O pins with built-in slew rate control, Schmitt-trigger inputs, and open-drain or push-pull outputs in a compact 24-pin SSOP package (3.9 mm width). Compared to discrete solutions requiring level shifters, pull-up resistors, and additional control logic, it reduces BOM count by approximately 30 components and saves ~250 mm² of board area in medium-density designs. Furthermore, its internal register map allows atomic read-modify-write operations via I2C, eliminating race conditions common in bit-banged implementations. This integration enhances reliability and simplifies firmware development, particularly in systems where footprint and EMI performance are constrained.
How does the Moisture Sensitivity Level (MSL) of 2 for the PCA9555DBQR influence handling procedures during reflow soldering?
With an MSL rating of 2, the PCA9555DBQR can withstand one year of ambient storage before baking becomes necessary if absorbed moisture exceeds 5% relative humidity equivalent. After opening the moisture-barrier bag, components must be soldered within 168 hours at ≤30°C/60% RH. If not used promptly, bake at 125°C for 24 hours before resealing. Skipping this step increases popcorning risk during lead-free reflow profiles (peak 245–250°C), which could crack the die attach or cause delamination. Proper handling per JEDEC J-STD-033 is essential to preserve solder joint integrity and device functionality.
What role does the Power-On Reset (POR) feature play in preventing false interrupts during startup sequences involving staggered power rail enables?
The PCA9555DBQR’s POR circuit holds the interrupt line inactive until VDD stabilizes above approximately 1.8V, ensuring that transient glitches during power ramp-up do not trigger spurious interrupts. In designs where peripherals enable at different voltages—such as a 1.8V MCU followed by a 3.3V sensor expander—this prevents premature wake-up events. Without POR, input transitions caused by slow-rising rails could be misinterpreted as valid user actions. This feature enhances system robustness by guaranteeing clean state initialization before normal operation begins.
How does the choice of pull-up resistor value affect both rise time and noise margin when interfacing the PCA9555DBQR over long I2C traces?
Optimal pull-up resistor values depend on bus length, capacitance, and desired data rate. For a 400 kHz I2C bus with 200 pF total capacitance, calculations suggest 1.8 kΩ yields a rise time near 500 ns—within fast-mode limits. Too high a resistance (>4.7 kΩ) slows rise time excessively, increasing susceptibility to electromagnetic interference and clock stretching; too low (<1 kΩ) draws excessive standby current (e.g., 3.3V/1kΩ = 3.3 mA total), wasting power. Simulation or measurement with an oscilloscope is advised to balance speed, power, and noise immunity for the specific layout.

Parts with Similar Specifications

The three parts on the right have similar specifications to Texas Instruments PCA9555DBQR

Product Attribute PCA9555DBQRG4 PCA9555DBR PCA9555DWRG4 PCA9555DWR
Part Number PCA9555DBQRG4 PCA9555DBR PCA9555DWRG4 PCA9555DWR
Manufacturer Luminary Micro / Texas Instruments Texas Instruments Texas Instruments Texas Instruments
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Base Product Number - DAC34H84 MAX500 ADS62P42
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C
Current - Output Source/Sink - - - -
Clock Frequency - - - -
Output Type - Current - Unbuffered Voltage - Buffered -
Interrupt Output - - - -
Mounting Type - Surface Mount Through Hole Surface Mount
Features - - - Simultaneous Sampling
Series - - - -
Voltage - Supply - - - -
Number of I/O - - - -
Interface - - - -
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Supplier Device Package - 196-NFBGA (12x12) 16-PDIP 64-VQFN (9x9)

PCA9555DBQR Datasheet PDF

Download PCA9555DBQR pdf datasheets and Texas Instruments documentation for PCA9555DBQR - Texas Instruments.

PCN Design/Specification
Datasheet Update 25/Jun/2014.pdf PCA9555 04/Sep/2018.pdf
PCN Obsolescence/ EOL
Mult Dev EOL 28/Mar/2023.pdf
HTML Datasheet
PCA9555.pdf

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Customer Reviews

Evaluation: 10 Articles

  • Nath***rooks
    Jun 11, 2026

    Installed this power component in a converter board. Output remained stable under different load conditions and thermal performance was better than expected.

  • Dani***alkerTech
    Jun 1, 2026

    Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.

  • Yuki***aka88
    May 26, 2026

    信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。

  • Stev***aker
    May 20, 2026

    Solid diode for power rectification. Works well in switching circuits.

  • Bran***Lewis
    May 11, 2026

    Compact FPGA with good performance. Suitable for basic signal processing tasks.

  • Oliv***arris
    May 7, 2026

    Reliable I/O expander. Works well in embedded control applications.

  • Jess***Jones
    Apr 17, 2026

    It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.

  • Mich***Smith
    Apr 17, 2026

    Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.

  • Aman***arris
    Apr 3, 2026

    It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.

  • Mike***nch
    Apr 3, 2026

    Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.

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Delivery Method

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Common Countries Logistic Time Reference
Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
Italy 5
Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.
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PCA9555DBQR Image

PCA9555DBQR

Texas Instruments
32D-PCA9555DBQR

Want a better price? Add to Cart and Submit RFQ now, we'll contact you immediately.

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