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Home Products Integrated Circuits (ICs)Specialized ICs~~PCA9555DBRG4~~

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PCA9555DBRG4 - Freescale / NXP Semiconductors

Name: Freescale / NXP Semiconductors PCA9555DBRG4
Brand: Freescale / NXP Semiconductors
SKU: PCA9555DBRG4
Availability: InStock
Rating: 5 (9 reviews)

Manufacturer Part Number: PCA9555DBRG4

Manufacturer: NXP Semiconductors

Allelco Part Number: 32D-PCA9555DBRG4

Warranty: 1 Year Allelco Warranty - Find out more

Stock Status:: 13,460 pcs available, New & Original

Parts Description: DAC91001

Data sheet: -

Category: Integrated Circuits (ICs) > Specialized ICs

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In stock: 13460

Specifications

PCA9555DBRG4 Tech Specifications
Freescale / NXP Semiconductors - PCA9555DBRG4 technical specifications, attributes, parameters and parts with similar specifications to Freescale / NXP Semiconductors - PCA9555DBRG4

Product Attribute	Attribute Value
Part Number	PCA9555DBRG4
Package	DAC91001
Description	DAC91001
Stock Condition	Get 13460 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

Frequently Asked Questions(FAQ)

How does the PCA9555DBRG4 compare to the PCA9535DBRG4 in terms of I/O configuration flexibility and interrupt handling for low-pin-count microcontroller applications?: The PCA9555DBRG4 offers dual 8-bit I/O ports with independent input and output configurations, supporting both push-pull and open-drain outputs, while the PCA9535DBRG4 provides only one 8-bit I/O port. This makes the PCA9555 more suitable for systems requiring bidirectional data buses or separate control and status signals. Both support interrupt-on-change functionality, but the PCA9555 allows individual masking per port, enabling finer-grained event detection. In terms of register layout and command protocol, they are compatible, allowing reuse of firmware with minor modifications. For designs needing expanded I/O without increasing GPIO count on the host MCU, the PCA9555DBRG4 provides a scalable advantage.

What are the key timing constraints when using the PCA9555DBRG4 in a multi-drop SMBus system operating at 400 kHz, and how do pull-up resistor values impact signal integrity?: The PCA9555DBRG4 operates reliably up to 400 kHz on the SMBus interface, with a maximum rise time (tr) of 300 ns specified under standard-mode conditions. To meet this, pull-up resistors must be chosen to limit rise time based on bus capacitance. For example, with a total bus capacitance of 200 pF, a 4.7 kΩ pull-up results in a tr of approximately 1.3 µs, exceeding the spec. A 1.5 kΩ resistor yields a rise time near 450 ns, which is acceptable. Lower resistance improves noise margin but increases power consumption. Proper resistor selection ensures reliable communication across multiple devices like the PCA9555DBRG4 without bus contention or arbitration failures.

Can the PCA9555DBRG4 be used in hot-swapping scenarios, and what precautions are necessary to protect against ESD and voltage transients?: The PCA9555DBRG4 does not inherently support hot-swap protection, but it includes built-in ESD protection up to ±2 kV HBM on I/O pins, which mitigates static discharge risks. However, external protection such as TVS diodes on VCC and I/O lines is recommended for robust hot-plug environments. Voltage surges during insertion can cause latch-up if the supply ramps too quickly; thus, a soft-start circuit or current-limiting power supply is advisable. Inputs should be clamped with Schottky diodes to VCC and GND when interfacing with unpowered peripherals. While functional in many hot-swap setups, the design must include additional circuitry to ensure long-term reliability with the PCA9555DBRG4.

What is the typical propagation delay from input change to interrupt assertion on the PCA9555DBRG4, and how does this affect real-time monitoring in embedded systems?: The PCA9555DBRG4 has a typical interrupt response delay of 1.5 µs from input transition to interrupt pin activation, with a maximum of 4 µs under worst-case conditions. This delay includes internal sampling and flag setting. For applications requiring sub-µs responsiveness, such as motor control feedback loops, this may be insufficient. However, for general-purpose I/O monitoring—like detecting button presses or sensor state changes—it is adequate. Designers should poll the interrupt status register shortly after the edge occurs to minimize missed events. Compared to polling-based approaches, interrupt-driven use of the PCA9555DBRG4 reduces CPU overhead but introduces small latency that must be accounted for in timing budgets.

How does the PCA9555DBRG4 handle bus contention when multiple masters attempt simultaneous access, and what mechanisms ensure deterministic behavior?: The PCA9555DBRG4 operates as a slave device on the SMBus and relies entirely on the protocol layer for arbitration. It does not implement any hardware-based collision detection or recovery logic beyond standard SMBus compliance. When two masters contend for the bus, the one transmitting a '0' instead of '1' loses arbitration and backs off, ensuring deterministic access. The PCA9555DBRG4 will only respond to its assigned 7-bit address (default 0x40) and ignore other transactions. This means system-level design must ensure master coordination and avoid prolonged bus occupancy by other slaves. The part itself does not add intelligence to resolve contention, so firmware or higher-layer protocols must manage scheduling to prevent repeated collisions involving the PCA9555DBRG4.

What are the recommended decoupling capacitor values and placement guidelines for stable operation of the PCA9555DBRG4 in compact PCB layouts?: The PCA9555DBRG4 requires a 0.1 µF ceramic capacitor placed as close as possible to the VCC and GND pins of the SSOP24 package to suppress high-frequency noise on the supply line. A second 10 µF tantalum or ceramic capacitor may be added near the board’s power entry point if multiple ICs share the same rail. Decoupling must account for trace inductance; thus, short, wide traces are essential. In dense layouts, placing vias adjacent to the capacitor pads minimizes loop area. Poor decoupling can lead to glitches on the reset line or erratic I/O behavior, especially during bus transitions. Following these practices ensures stable operation across the full temperature range and clock frequency options supported by the PCA9555DBRG4.

Can the PCA9555DBRG4 drive inductive loads directly, and what external components are needed to prevent damage from back-EMF?: The PCA9555DBRG4 cannot safely drive inductive loads such as relays or solenoids directly due to limited sink/source current capability (typically 25 mA per pin). Inductive kickback can exceed absolute maximum ratings and cause permanent damage. To protect the device, flyback diodes must be connected across the load in reverse polarity. Additionally, series resistors or buffer transistors (e.g., MOSFETs) should isolate the PCA9555DBRG4 from high-current paths. For example, driving a 5V relay coil rated at 70 mA requires an external NPN transistor with a base resistor and flywheel diode. Using the PCA9555DBRG4 in this way extends its utility while maintaining reliability through proper interface design.

What is the effect of operating the PCA9555DBRG4 at elevated temperatures on its I/O switching characteristics and power dissipation?: At temperatures above 85°C, the PCA9555DBRG4 exhibits increased propagation delays in I/O transitions due to degraded carrier mobility in CMOS transistors. Output rise and fall times may extend by up to 30% compared to room temperature operation. Power dissipation also rises slightly with temperature due to leakage currents, though this is negligible in most applications. Thermal derating is minimal for standard operation, but continuous high-load conditions on multiple I/O pins can raise junction temperature significantly in poorly ventilated enclosures. Ensuring adequate airflow or spacing around the SSOP24 package helps maintain performance. Designers should verify timing margins under worst-case thermal conditions when relying on precise I/O synchronization with the PCA9555DBRG4.

How does the PCA9555DBRG4 support mixed-voltage systems, and what level translation is required when interfacing with 3.3V logic?: The PCA9555DBRG4 supports a wide supply voltage range from 2.3V to 5.5V, making it compatible with both 3.3V and 5V systems. Its I/O pins are 5V-tolerant when powered at 3.3V, meaning they can accept input voltages up to 5.5V without damage—this simplifies interfacing with 5V sensors or buttons. However, when the PCA9555DBRG4 is operated at 3.3V and drives a 5V load, the output high level may drop below 5V, potentially causing logic errors. In such cases, a bidirectional level shifter or open-drain configuration with an external pull-up to 5V ensures clean signal translation. This flexibility enables the PCA9555DBRG4 to serve as a bridge in heterogeneous voltage environments without requiring additional ICs for basic connectivity.

What is the significance of the default I²C address of 0x40 for the PCA9555DBRG4, and how can it be modified in systems with multiple similar devices?: The PCA9555DBRG4 defaults to I²C address 0x40 (binary 1000000) when all address pins (A0–A2) are grounded. This address occupies a common position among many I²C devices, increasing collision risk in multi-slave systems. To avoid conflicts, designers must configure the A0–A2 pins to unique states: logic low (0) or high (1), corresponding to bits 2, 1, and 0 of the address byte. For instance, tying A0 high changes the LSB, shifting the address to 0x41. With eight possible combinations, up to eight PCA9555DBRG4 devices can coexist on the same bus. This addressing scheme is critical for scalable expansion and must be verified during system bring-up to prevent communication failures due to duplicate addresses.

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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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Common Countries Logistic Time Reference
Region	Country	Logistic Time(Day)
America	United States	5
America	Brazil	7
Europe	Germany	5
	United Kingdom	4
	Italy	5
Oceania	Australia	6
Oceania	New Zealand	5
Asia	India	4
Asia	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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PCA9555DBRG4

Freescale / NXP Semiconductors
32D-PCA9555DBRG4

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Please refer to the English Version as our Official Version.Return

PCA9555DBRG4 - Freescale / NXP Semiconductors

Specifications

Frequently Asked Questions(FAQ)

Customers Also Interested in

Recommended Products

Customer Reviews

Evaluation: 10 Articles

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

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.

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。

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

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

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

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.

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.

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.

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.