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HomeProductsIntegrated Circuits (ICs)Interface - I/O ExpandersPCA9555DB
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PCA9555DB - Texas Instruments

Manufacturer Part Number
PCA9555DB
Manufacturer
Texas Instruments
Allelco Part Number
32D-PCA9555DB
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
17,294 pcs available, New & Original
Parts Description
IC XPNDR 400KHZ I2C SMBUS 24SSOP
Package
24-SSOP
Data sheet
PCA9555DB.pdf

HTML Datasheet

PCA9555.pdf
RoHs Status
ROHS3 Compliant
Compare
Our certification
In stock: 17294
  • Unit Price: $1.805
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
1+ $1.805 $1.81
10+ $1.572 $15.72
30+ $1.434 $43.02
100+ $1.294 $129.40
500+ $1.229 $614.50
1000+ $1.20 $1,200.00
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

PCA9555DB Tech Specifications
Texas Instruments - PCA9555DB technical specifications, attributes, parameters and parts with similar specifications to Texas Instruments - PCA9555DB

Product Attribute Attribute Value
Manufacturer Texas Instruments
Voltage - Supply 2.3V ~ 5.5V
Supplier Device Package 24-SSOP
Series -
Package / Case 24-SSOP (0.209", 5.30mm Width)
Package Tube
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) 1 (Unlimited)
REACH Status REACH Unaffected
ECCN EAR99
HTSUS 8542.39.0001

Parts Introduction

PCA9555DB Image
PCA9555DB (1)

Manufacturer Part Number

PCA9555DB

Manufacturer

texas-instruments

Introduction

PCA9555DB is an I2C and SMBus compatible 16-bit I/O expander designed to provide general-purpose remote I/O expansion for microcontroller applications.

Product Features and Performance

16 I/O pins that can be configured individually

I2C and SMBus interface support

Interrupt output capability for event-driven applications

Power-on reset (POR) feature

Push-Pull output type

Max clock frequency of 400 kHz

Wide voltage supply range from 2.3V to 5.5V

Operating temperature between -40°C and 85°C

Product Advantages

Increases the number of I/O ports available

Low power consumption

Flexible interfacing with both I2C and SMBus

Suitable for a wide range of operating conditions

Key Technical Parameters

Number of I/O: 16

Interface: I2C, SMBus

Output Type: Push-Pull

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

High reliability with built-in power-on reset

Designed for robust operation across a wide range of temperatures

Compatibility

Compatible with various microcontrollers supporting I2C or SMBus

Surface mount package compatible with standard PCB technologies

Application Areas

Remote sensing

Server management

Industrial control

Automotive systems

Robotics

Product Lifecycle

Status: Obsolete

Replacement or upgrade options should be evaluated as this model may no longer be manufactured

Several Key Reasons to Choose This Product

Enhances microcontroller functionality by extending I/O capability

Easy to integrate with existing I2C or SMBus systems

Robust design suitable for demanding applications

POR feature ensures reliable performance after power resets

Broad compatibility and ease of mounting with surface mount SSOP package

Frequently Asked Questions(FAQ)

What is the maximum allowable supply voltage for the PCA9555DB I/O expander, and how does this impact system-level power budgeting in mixed-voltage environments?
The PCA9555DB supports a supply voltage range from 2.3V to 5.5V, making it suitable for systems operating across low-power 3.3V logic domains and legacy 5V interfaces. This wide tolerance allows integration into mixed-voltage platforms without additional level-shifting circuitry when interfacing with compatible devices. However, exceeding 5.5V risks damaging the device, so proper voltage regulation or clamping must be ensured at the board layout stage. Designers should verify that all connected peripherals operate within this window to maintain signal integrity and prevent latch-up conditions.
How does the clock frequency of 400 kHz on the PCA9555DB compare to standard I2C speeds, and what are the practical implications for bus loading and timing margin in dense sensor networks?
The PCA9555DB operates at a 400 kHz clock rate, which aligns with Fast-mode I2C defined by the I2C specification. This is significantly faster than Standard-mode (100 kHz) but slower than Fast-mode Plus (1 MHz) or High-speed mode (3.4 MHz). In applications like industrial sensor arrays or automotive control units where multiple PCA9555DB devices share a single I2C bus, the 400 kHz limitation may introduce latency under high device counts. Each additional slave adds propagation delay due to pull-up resistor loading and capacitance, potentially reducing usable bandwidth. For designs requiring higher throughput, parallel buses or alternative protocols may be preferable unless the simplicity of I2C outweighs speed requirements.
What output drive strength options are available on the PCA9555DB pins, and how should these be matched to load characteristics such as capacitive switching or long trace routing?
The PCA9555DB provides configurable output current capability of 10mA source and 25mA sink per pin. These values represent typical drive levels under specified load conditions and must be considered when driving LEDs, relays, or capacitive loads. Driving a 100pF load at full swing over a 5cm PCB trace introduces RC time constants that may slow edge rates; insufficient slew rate can cause electromagnetic interference (EMI) or excessive power dissipation during transitions. Engineers should simulate worst-case scenarios using estimated parasitic capacitance and select series termination if needed. Exceeding thermal limits due to continuous high-current sinking—such as activating multiple relays—may require external buffering even within rated current specifications.
Can the PCA9555DB generate interrupts based on pin state changes, and how does this feature improve system responsiveness compared to polling-based architectures?
Yes, the PCA9555DB includes an active-low interrupt output (INT) that asserts whenever any input pin transitions from low to high or vice versa, depending on configuration registers. This enables event-driven processing instead of periodic polling, reducing CPU overhead and improving real-time performance in microcontroller-based systems. For example, in a touchscreen controller application using PCA9555DB to monitor GPIO states, interrupt-driven reads eliminate wasted cycles between user interactions. The interrupt remains asserted until cleared by reading status registers, requiring careful firmware handling to avoid missed events during burst activity. Compared to polling every 1ms across 16 lines, interrupt mode can reduce average current consumption by orders of magnitude in sleep-dominated workloads.
What role does the Power-On Reset (POR) feature play in the initialization sequence of the PCA9555DB, and how does it affect startup reliability in battery-powered devices?
The PCA9555DB incorporates a Power-On Reset circuit that ensures internal registers default to known states upon initial power-up or brown-out recovery. During POR activation (typically lasting tens of milliseconds), all outputs are forced into high-impedance or safe logic levels to prevent glitches on connected loads. This prevents unintended activation of actuators like motors or solenoids before firmware configures direction registers. In battery-operated systems where voltage ramps slowly due to large decoupling capacitors or weak charging circuits, POR guarantees deterministic behavior rather than unpredictable register contents. Designers should ensure supply rise times remain within datasheet recommendations to fully reset internal latches before enabling I2C communication.
How does the Moisture Sensitivity Level (MSL) rating of MSL 1 for the PCA9555DB influence storage and handling procedures during manufacturing?
With an MSL rating of 1, the PCA9555DB is classified as non-hygroscopic and does not require special dry packaging, unlimited floor life after opening, or bake-out prior to reflow soldering. This simplifies inventory management and reduces costs associated with moisture-sensitive component handling protocols. However, while technically tolerant, best practices still recommend storing parts in sealed containers with desiccant during prolonged storage (>6 months) if environmental humidity exceeds 60% RH. Manufacturers often apply conformal coatings in harsh environments, which further mitigates risk. Still, MSL 1 indicates robustness under normal assembly flows but does not imply immunity to ESD damage—proper handling per JEDEC JESD625 remains essential.
Are there any recommended substitutes for the PCA9555DB, and how do they compare in terms of electrical compatibility and functional equivalence?
Two notable substitutes include the MAX7312AAG+T from Maxim Integrated and the PCA9555DB itself (likely referencing alternate TI part numbers). While both support I2C/SMBus interfaces and offer similar pin counts, differences exist: the MAX7312AAG+T typically features lower output drive currents (~8mA) and lacks built-in POR functionality, requiring external supervision circuitry. Additionally, its interrupt structure may differ in polarity or masking capabilities. Substitution should involve verifying register maps, interrupt behaviors, and thermal profiles under worst-case loads. Cross-referencing application notes and performing signal integrity tests on target hardware ensures compatibility beyond surface-level pin compatibility.
What considerations arise when cascading multiple PCA9555DB devices on the same I2C bus, particularly regarding address assignment and bus contention risks?
The PCA9555DB provides three hardware address pins (A0–A2), allowing up to eight unique addresses (0x20–0x27) when pulled high/low appropriately. Cascading more than eight requires either secondary buses or software-based multiplexing. Bus contention occurs only during simultaneous transmit/receive operations, but since I2C uses open-drain drivers, physical collisions are avoided through arbitration. However, misconfigured addresses can lead to unintended writes or failed reads. Engineers should implement diagnostic routines that poll each expected address sequentially during initialization and validate responses against expected ACK pulses. Pull-up resistor selection becomes critical with multiple devices: higher capacitance increases rise times, potentially violating setup/hold times at 400 kHz. A balanced trade-off between resistance value and noise margin must be struck based on total bus capacitance measured via oscilloscope probing.

Parts with Similar Specifications

The three parts on the right have similar specifications to Texas Instruments PCA9555DB

Product Attribute PCA9555DBQR PCA9555DB,112 PCA9555DBQRG4 PCA9555DBR
Part Number PCA9555DBQR PCA9555DB,112 PCA9555DBQRG4 PCA9555DBR
Manufacturer Texas Instruments NXP USA Inc. Luminary Micro / Texas Instruments Texas Instruments
Clock Frequency - - - -
Number of I/O - - - -
Features - - - Simultaneous Sampling
Voltage - Supply - - - -
Series - - - -
Output Type - Current - Unbuffered Voltage - Buffered -
Mounting Type - Surface Mount Through Hole Surface Mount
Supplier Device Package - 196-NFBGA (12x12) 16-PDIP 64-VQFN (9x9)
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Base Product Number - DAC34H84 MAX500 ADS62P42
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Interrupt Output - - - -
Current - Output Source/Sink - - - -
Interface - - - -
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C

PCA9555DB Datasheet PDF

Download PCA9555DB pdf datasheets and Texas Instruments documentation for PCA9555DB - Texas Instruments.

PCN Design/Specification
Datasheet Update 25/Jun/2014.pdf PCA9555 04/Sep/2018.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 Time

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Delivery Cost

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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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PCA9555DB Image

PCA9555DB

Texas Instruments
32D-PCA9555DB

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

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