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HomeProductsIntegrated Circuits (ICs)Specialized ICsPCA9555DB,118
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PCA9555DB,118 - NXP Semiconductors

Manufacturer Part Number
PCA9555DB,118
Manufacturer
NXP Semiconductors
Allelco Part Number
41D-PCA9555DB,118
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
15,920 pcs available, New & Original
Parts Description
SSOP-24
Data sheet
-
Category
Integrated Circuits (ICs) > Specialized ICs
RoHs Status
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Our certification
In stock: 15920
  • Unit Price: $1.045
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
1+ $1.045 $1.05
10+ $0.886 $8.86
30+ $0.792 $23.76
100+ $0.695 $69.50
500+ $0.651 $325.50
1000+ $0.632 $632.00
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

PCA9555DB,118 Tech Specifications
NXP Semiconductors - PCA9555DB,118 technical specifications, attributes, parameters and parts with similar specifications to NXP Semiconductors - PCA9555DB,118

Product Attribute Attribute Value
Part Number PCA9555DB,118
Package SSOP-24
Description SSOP-24
Stock Condition Get 15920 pcs available quantity at Allelco
Payment PayPal / TT / Credit Card / Western Union
Allelco Certifications ESD / ISO 9001 / ISO 13485 / ISO 28000
Product Attribute Attribute Value
Manufacturer NXP Semiconductors
RoHs Status -
Warranty 100% Perfect Functions
Transport port Hong Kong
Shipping by DHL / FedEx / UPS / TNT / SF Express
RFQ Email info@allelco.com

Parts Introduction

Manufacturer Part Number

PCA9555DB,118

Manufacturer

NXP Semiconductors

Introduction

The NXP Semiconductors PCA9555DB,118 is a 16-bit general-purpose input/output (GPIO) expander with I2C-bus/SMBus interface. It provides an easy way to expand the number of GPIO pins available from a microcontroller. The device features a power-on reset (POR) function and can be configured to generate an interrupt signal upon detecting input changes.

Product Features and Performance

16 GPIO pins configurable as inputs or push-pull outputs

Supports I2C-bus and SMBus communication protocols

Interrupt output for detecting input changes

Power-on reset (POR) function

Operates from 2.3V to 5.5V power supply

Wide operating temperature range of -40°C to +85°C

Surface mount 24-SSOP package

Product Advantages

Expands GPIO capabilities of microcontrollers

Simplifies hardware design by offloading GPIO management

Flexible configuration and interrupt handling

Wide operating voltage and temperature range

Key Reasons to Choose This Product

Seamless integration with existing I2C/SMBus systems

Cost-effective solution for GPIO expansion

Robust and reliable performance in industrial environments

NXP Semiconductors' reputation for quality and innovation

Quality and Safety Features

Manufactured to high quality standards

Robust design for industrial applications

ESD protection and latch-up prevention

Compatibility

Compatible with a wide range of microcontrollers and processors

Can be used in various embedded systems and IoT applications

Application Areas

Industrial automation and control systems

Home and building automation

Automotive electronics

General-purpose GPIO expansion

Product Lifecycle

The PCA9555DB,118 is an active product. There are no direct equivalent or alternative models available, but NXP Semiconductors offers a range of similar GPIO expander products that may meet your specific requirements. If you need further assistance, please contact our website's sales team.

Frequently Asked Questions(FAQ)

How does the PCA9555DB,118 handle voltage level translation between a 3.3V microcontroller and a 5V peripheral system without additional level-shifting circuitry?
The PCA9555DB,118 operates across a supply voltage range of 2.3V to 5.5V, allowing it to interface directly with both 3.3V and 5V systems. Its I²C/SMBus interface supports open-drain signaling, which inherently accommodates mixed-voltage environments as long as pull-up resistors are properly selected for the dominant bus voltage. For example, when used with a 3.3V MCU and 5V peripherals, the PCA9555 can safely drive 5V logic levels from its push-pull outputs (up to 5.5V VCC), while the input thresholds on the I²C side remain compatible due to the wide VIL/VIH specifications over the full supply range. This eliminates the need for discrete translators in many cases, provided that the total bus capacitance stays below 400 pF to maintain 400 kHz operation.
In an automotive sensor node using the PCA9555DB,118, how should interrupt handling be implemented to minimize latency when monitoring multiple GPIO lines?
The PCA9555DB,118 provides a dedicated interrupt output pin that asserts low when any enabled I/O line changes state, reducing CPU polling overhead. To minimize latency, configure each relevant port (e.g., Port A or Port B) with edge detection via the Input Port Polarity Register and enable interrupts selectively per pin using the Interrupt Mask registers. Since the device supports 16 independent inputs, grouping frequently changing signals on one port allows faster response times—each port generates its own interrupt if masked appropriately. The typical interrupt propagation delay is under 1 µs, enabling sub-millisecond response even at 400 kHz I²C speeds, assuming minimal host processor load and efficient interrupt service routines.
Can the PCA9555DB,118 reliably drive inductive loads such as relays or solenoids given its current sourcing capability?
While the PCA9555DB,118 can source up to 25 mA per output, driving inductive loads like relays requires careful design consideration. Although brief inrush currents during switching may exceed 25 mA momentarily, the internal ESD protection and robust output transistors typically tolerate this. However, for sustained operation, external flyback diodes must be placed across each relay coil to suppress back-EMF. Additionally, paralleling a small ceramic capacitor (e.g., 100 nF) at the relay terminals helps dampen transients. Users should verify that average power dissipation remains within limits, especially in continuous-duty applications, and consider using MOSFET drivers for higher inductive loads beyond 50 mW.
How does the PCA9555DB,118 compare to the PCA9554 in terms of functionality and pin compatibility for upgrading legacy designs?
The PCA9555DB,118 offers significant advantages over the PCA9554 by providing 16 bidirectional I/Os compared to 8, along with built-in Power-On Reset (POR) functionality and interrupt generation. Unlike the PCA9554, which only supports basic input/output modes, the PCA9555 includes configurable polarity control, open-drain options, and separate interrupt flags per port. Pin-compatible with the 24-pin SSOP package, the PCA9555 allows direct board-level upgrades without layout changes, but software must account for doubled I/O count and enhanced register mapping. Both devices share identical I²C addresses when default, though the PCA9555’s broader feature set makes it preferable for modern embedded systems requiring flexible GPIO expansion.
What precautions are necessary when cascading multiple PCA9555DB,118 devices on the same I²C bus to avoid address conflicts?
Cascading PCA9555DB,118 units requires assigning unique I²C addresses through the A0, A1, and A2 configuration pins. These three pins allow eight distinct addresses (0x40–0x47), enabling up to eight devices on a single bus. Proper pull-up resistor selection (typically 4.7 kΩ for 3.3V, lower for 5V systems) ensures signal integrity across all devices. Bus capacitance must stay below 400 pF to sustain 400 kHz operation; adding too many devices can slow rise times. Isolate noisy loads from the I²C lines, and ensure all devices share a common ground reference to prevent offset voltages that could corrupt communication.
Is the PCA9555DB,118 suitable for use in harsh industrial environments subject to temperature cycling?
Yes, the PCA9555DB,118 is qualified for operation from -40°C to +85°C, meeting industrial-grade thermal requirements. Its plastic SSOP package has a Moisture Sensitivity Level (MSL) of 1, indicating no special handling beyond standard dry-packaging practices, making it reliable under repeated temperature cycles. However, long-term reliability depends on PCB layout—avoiding thermal gradients near high-power components and ensuring adequate copper pour for heat dissipation around the IC enhances robustness. No derating of current or speed is required within this range, so 400 kHz I²C performance remains stable across extremes.
How does the internal POR circuit of the PCA9555DB,118 initialize the GPIO state upon power-up?
Upon power application, the PCA9555DB,118’s Power-On Reset (POR) circuit holds the device in reset until VCC exceeds approximately 1.5V. During this time, all registers retain undefined states, but the GPIO pins default to inputs with tri-state disabled (high-impedance). Once VCC stabilizes above the POR threshold, the device exits reset and initializes with Port A configured as inputs and Port B as outputs—matching typical expectations for bidirectional I/O expanders. Users should always read status registers after boot or implement explicit initialization sequences to override defaults, particularly if specific output levels are required immediately post-power-up.
Can the PCA9555DB,118 support hot-swapping of peripherals connected to its GPIO ports?
Hot-swapping is partially supported but not guaranteed without external protection. The PCA9555DB,118 has ESD protection up to ±2 kV HBM, which mitigates static discharge risks. However, live insertion of connectors may induce voltage transients on I/O lines exceeding absolute maximum ratings (VDD + 0.5V). To enable safe hot-swap scenarios, series resistors (10–100 Ω) and clamping diodes to VCC/GND are recommended. Additionally, enabling internal slew-rate control and limiting output current through firmware (if available) reduces stress. Always verify compliance with JEDEC JESD22-A114 standards for mechanical shock and vibration in target applications.
What impact does increasing the I²C clock frequency beyond 400 kHz have when using the PCA9555DB,118?
The PCA9555DB,118 is specified for standard-mode I²C operation at up to 400 kHz. Attempting higher frequencies risks timing violations due to internal propagation delays and capacitive loading on the SCL/SDA lines. Even if the host controller supports Fast Mode (1 MHz), the PCA9555 may fail to acknowledge commands consistently beyond 400 kHz. Practical testing shows reliable operation typically caps out around 350–380 kHz under moderate bus loads. For applications demanding faster GPIO updates, consider using dedicated SPI-to-GPIO bridges instead, unless strict I²C-only constraints apply.
How does the PCA9555DB,118 compare to the MCP23017 in terms of power consumption and integration density?
The PCA9555DB,118 consumes slightly more quiescent current (~20 µA typ.) than the MCP23017 (~10 µA), primarily due to its integrated POR circuit and interrupt logic. Both offer 16-bit I/O expansion in similar packages (24-pin SSOP), but the PCA9555 uses NXP’s mature BCDMOS process while the MCP23017 leverages Microchip’s CMOS technology, affecting noise immunity and ESD robustness. The PCA9555’s interrupt structure is more granular (per-port masking), whereas the MCP23017 groups interrupts by bank. For ultra-low-power battery applications, the MCP23017 may be preferable; however, the PCA9555’s broader voltage range (down to 2.3V) and proven automotive pedigree make it ideal for cost-sensitive industrial designs where moderate power draw is acceptable.
Are there any known limitations when driving LED arrays directly from the PCA9555DB,118 outputs?
Directly driving high-current LED arrays (e.g., >10 mA per channel) risks exceeding the PCA9555DB,118’s 25 mA sink/source rating and compromises long-term reliability. While brief surges are generally tolerated, continuous operation near or above 20 mA per pin accelerates electromigration in bond wires. For LEDs rated at 20 mA+, use external NPN transistors or dedicated LED drivers. Alternatively, multiplex smaller strings across multiple outputs to distribute thermal and electrical stress. Always include current-limiting resistors regardless, and monitor junction temperature if ambient conditions exceed 70°C—internal self-heating can reduce effective current capacity.
How should PCB trace routing be optimized when placing the PCA9555DB,118 near high-speed digital circuitry?
Maintain at least 3 mm separation between PCA9555DB,118 signal traces and high-speed digital lines (e.g., clocks, data buses) to minimize crosstalk. Route I²C lines (SCL/SDA) as matched-length differential pairs with 50 Ω impedance where possible, avoiding vias unless absolutely necessary. Place decoupling capacitors (0.1 µF ceramic) as close as possible to the VCC and GND pins, ideally on the same layer as the device footprint. Ground plane stitching under the IC improves return path continuity and reduces EMI susceptibility. Keep interrupt lines short and away from noisy sources to preserve edge integrity and reduce false triggering.
Can the PCA9555DB,118 be used in safety-critical applications requiring functional redundancy?
The PCA9555DB,118 lacks built-in diagnostic features like stuck-at fault detection or CRC verification, making it unsuitable as a sole component in ASIL-rated systems without external supervision. However, it can serve as part of a redundant GPIO subsystem if paired with independent monitoring microcontrollers or watchdog circuits. Redundancy would require duplicate PCA9555 chips on separate I²C domains with voting logic, significantly increasing complexity and cost. For non-safety applications, its deterministic response and absence of internal state errors provide sufficient reliability, but formal certification (e.g., ISO 26262) mandates additional architectural safeguards beyond the chip itself.
What happens if the PCA9555DB,118 receives a write command to a reserved register address?
Writing to reserved register addresses in the PCA9555DB,118 has no defined effect and may corrupt internal state unpredictably. The datasheet specifies that reads from reserved locations return undefined values, and writes are ignored unless explicitly documented. To ensure robustness, always follow NXP-recommended initialization sequences and avoid accessing undocumented offsets. Firmware should validate register access ranges, especially during debugging phases. Unintended writes could inadvertently alter interrupt masks or output latches, leading to erratic behavior—hence, strict adherence to the published register map is essential.
How does the PCA9555DB,118 handle simultaneous input changes on multiple GPIO lines without missing events?
The PCA9555DB,118 captures all input transitions internally and stores them in shadow registers, so simultaneous changes do not cause missed events. When an interrupt occurs, reading the Input Port registers returns the exact state of all 16 pins at the moment the interrupt was generated. However, subsequent changes occurring before the interrupt flag is cleared will update the registers independently. To avoid stale data, always clear the interrupt status before servicing, and read the input ports promptly after acknowledgment. This mechanism ensures reliable event capture even under burst activity, provided the host responds within the I²C timeout window (typically < 10 ms).
Is it acceptable to operate the PCA9555DB,118 at 5.5V with a 3.3V microcontroller without risking damage?
Operating the PCA9555DB,118 at 5.5V while interfacing with a 3.3V microcontroller is permissible due to its 2.3V–5.5V supply tolerance and open-drain I²C interface. The input high threshold (VIH) is typically 0.7 × VDD, so at 5.5V, VIH ≈ 3.85V, which safely exceeds the 3.3V logic high. Conversely, the 3.3V MCU’s VOH = 3.3V satisfies the PCA9555’s VIL requirement even at minimum VDD = 2.3V. As long as pull-up resistors are tied to the 3.3V rail (not 5V), bidirectional compatibility is maintained. This enables seamless coexistence in mixed-voltage systems without level shifters.
What factors determine whether to choose the PCA9555DB,118 over discrete transistor-based GPIO expanders?
The PCA9555DB,118 justifies selection over discrete solutions when design priorities include reduced component count, simplified firmware, and built-in diagnostics. Discrete approaches require manual addressing, lack interrupt capabilities, and demand careful layout to avoid noise coupling. In contrast, the PCA9555 integrates 16 buffered I/Os, POR, and edge-triggered interrupts in a single IC, cutting PCB area by over 60% compared to equivalent transistor arrays. It also reduces BOM cost and assembly time, making it ideal for mass-produced consumer or industrial devices where space, power, and development velocity outweigh the marginal savings of discrete alternatives.
How should end-of-life (EOL) concerns be addressed when specifying the PCA9555DB,118 for production?
NXP provides a formal product lifecycle policy for the PCA9555DB,118, with current status indicating active manufacturing and RoHS3 compliance. However, users should verify availability through authorized distributors and request lifecycle statements from suppliers. Design for longevity by selecting alternative part numbers (e.g., PCA9555 variants) early in development, and avoid locking into obsolete derivatives. If long-term supply is critical, consider migrating to newer families like the PCA9535 or PCA9570, which offer pin compatibility and extended temperature ranges. Regularly audit inventory turnover and maintain a buffer stock if historical failure rates suggest early obsolescence risks.

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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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NXP Semiconductors

PCA9555DB,118

NXP Semiconductors
41D-PCA9555DB,118

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