PCA9543APW,118

NXP Semiconductors PCA9543APW,118 — 2‑Channel I2C‑bus Switch/Multiplexer with Interrupt Logic (TSSOP‑14)

The NXP Semiconductors PCA9543APW,118 is a compact, production‑proven I2C‑bus switch/multiplexer that helps engineers segment, expand, and control shared I2C networks with confidence. Belonging to the PCA9543A family, this device integrates two downstream I2C channels, an upstream interrupt output, per‑channel downstream interrupt inputs, and an active‑low reset. It operates from 2.3 V to 5.5 V and supports Standard‑ and Fast‑mode I2C up to 400 kHz, making it a dependable fit for embedded, consumer, and industrial designs. The “PW,118” ordering code denotes the 14‑pin TSSOP package supplied in tape‑and‑reel for automated assembly.

Engineers choose the PCA9543APW,118 to resolve address conflicts, isolate noisy or capacitive segments, and selectively connect a single upstream master to one or both downstream buses. Sourcing managers value its active lifecycle status, RoHS compliance, and broad ecosystem support, while the surface‑mount TSSOP‑14 package minimizes board area and simplifies manufacturing.

Highlights at a Glance

• Manufacturer/Brand: NXP Semiconductors
• Series: PCA9543A
• Category: Interface – I2C Switches / Multiplexers
• Function: 2‑channel I2C‑bus switch / multiplexer with interrupt logic
• Supply voltage (VCC): 2.3 V to 5.5 V
• I2C speed: Up to 400 kHz (Standard‑/Fast‑mode)
• Channels: Two downstream channels, individually or simultaneously selectable
• Addressing: Two hardware address pins (A0, A1) for up to four device addresses on the same bus
• Control: Active‑low RESET
• Interrupt: Upstream INT output; downstream INT0 and INT1 inputs
• Package: TSSOP‑14 (PW code), Tape & Reel (,118)
• Operating temperature: −40°C to +85°C
• Mounting: Surface Mount; 14 pins
• RoHS: RoHS compliant (Pb‑free)

Key Features and Specifications

Functional Features that Simplify I2C Architectures

• Two downstream I2C channels: Connect a single upstream master to one or both downstream buses. This allows segmentation of I2C peripherals by function, location, or noise profile.
• Flexible channel selection: Either channel can be enabled independently, and both channels may be enabled at the same time when required by the system.
• Address conflict mitigation: By isolating devices onto separate channels, the PCA9543APW,118 helps resolve duplicate I2C addresses on a shared system.
• Interrupt aggregation: Downstream lines (INT0/INT1) can signal events from either channel and present a consolidated INT to the upstream controller for efficient servicing.
• Hardware reset: An active‑low RESET input forces the device to a known state, simplifying robust startup and recovery from bus errors.
• Scalable addressing: Two address pins (A0, A1) provide up to four unique address combinations, enabling multiple PCA9543A devices on the same upstream bus.

Electrical and Timing Parameters

• Operating supply range: 2.3 V to 5.5 V
• I2C speed: Standard‑ and Fast‑mode, up to 400 kHz
• Logic levels: I2C‑bus compatible
• Operating temperature: −40°C to +85°C

Note: Detailed parameters such as on‑resistance, channel leakage, and timing margins should be taken from the NXP datasheet. Values not listed above are not specified here.

Package and Handling

• Package: TSSOP‑14 (PW)
• Packaging: Tape & Reel (ordering suffix “,118”) for automated pick‑and‑place
• Pin count: 14
• Mounting: Surface Mount

How the NXP PCA9543APW,118 Works

The PCA9543APW,118 presents a single upstream I2C interface to the host and internally routes that interface to one or both downstream channels. Selection is performed over the I2C bus, allowing software control of the active channel(s). This architecture is ideal for:

• Isolating capacitance to maintain I2C signal integrity in larger systems
• Grouping peripherals by function (e.g., sensors on channel 0, memory devices on channel 1)
• Enabling the host to switch context among multiple peripheral clusters without rewiring

Two hardware address pins (A0, A1) allow up to four PCA9543A devices to share the same upstream bus, each reachable at a unique I2C address. System designers can scale to as many as eight downstream segments by deploying multiple PCA9543A devices, subject to overall bus topology and timing considerations.

The integrated interrupt logic streamlines event handling. Each downstream bus exposes its interrupt line (INT0, INT1) to the switch. When a device on a downstream bus asserts an interrupt, the PCA9543A conveys a combined interrupt (INT) to the upstream controller, helping the host respond promptly while reducing GPIO usage.

The active‑low RESET input ensures the device can be returned to a default state during power‑up sequencing or after a bus fault. Coupled with software‑driven channel selection, RESET contributes to predictable, recoverable bus behavior in the field.

Applications and Use Cases

• I2C bus expansion and isolation: Build larger systems by segmenting loads to keep bus capacitance and noise in check.
• Address conflict resolution: Place same‑address peripherals on different channels so the master can communicate with each independently.
• Multi‑segment industrial and consumer systems: Partition sensors, EEPROMs, or converters by position or role within a device or chassis.
• Peripheral selection: Dynamically connect to different I2C peripherals such as sensors, EEPROMs, and ADC/DACs based on operating mode.

Example scenarios include modular sensing platforms, configurable instrumentation, rack‑based subsystems, and consumer devices that share a single host across multiple peripheral clusters.

Design‑In Guidelines and Best Practices

While the PCA9543APW,118 is straightforward to integrate, careful system design ensures robust I2C performance.

Bus Segmentation and Pull‑Ups

• Use appropriate pull‑up resistors on the upstream bus and on each downstream channel. Because each channel is selectively connected, each segment should meet I2C rise‑time and current requirements independently.
• Keep total bus capacitance within I2C‑mode limits (e.g., for 400 kHz Fast‑mode). Distribute devices across channels to reduce capacitive loading.

Address Planning

• With A0 and A1 address pins, up to four PCA9543A devices can share one upstream I2C bus. Plan address pin strapping early to avoid conflicts with other I2C devices.

Reset and Power Sequencing

• Connect RESET to the system reset supervisor or to a GPIO for recovery from fault conditions. This ensures the switch powers up in a known state before the host enumerates downstream devices.

Interrupt Integration

• Route INT to the host if you plan to use downstream interrupts. Fan‑in of INT0/INT1 through the PCA9543A helps consolidate multiple event lines to a single host pin.

Layout and EMC Considerations

• Place decoupling capacitors close to the device’s VCC pin(s) as recommended in the datasheet.
• Maintain short, direct I2C traces with controlled impedance where possible. Avoid stubs on the active segments; use the channel architecture to create clean point‑to‑point paths.

Note: Specific electrical characteristics not listed here (e.g., propagation delays, channel on‑resistance) must be obtained from the NXP datasheet. Where not provided in this overview, values are “Not specified in datasheet” for the purposes of this summary.

Lifecycle, Availability, and Ordering

• Lifecycle status: Active (per NXP Semiconductors)
• Compliance: RoHS compliant; Pb‑free
• Ordering code: PCA9543APW,118
• PW: TSSOP‑14 package
• ,118: Tape & Reel packaging
• Availability: Varies by distributor; package code “118” denotes tape‑and‑reel. Consult authorized channels for current stock and pricing.

For production planning, the TSSOP‑14 footprint and standard tape‑and‑reel format make the PCA9543APW,118 suitable for automated SMT lines. Always verify the latest lifecycle and availability directly with NXP or franchised distributors when locking a BOM.

Approved Alternates and Footprint Notes

• Texas Instruments TCA9543A: Functionally similar 2‑channel I2C switch with interrupt. Verify electrical limits, addressing behavior, and package options.
• NXP PCA9543AD,118: Same function in an SOIC package. Footprint differs from TSSOP‑14; check land patterns and assembly rules.

Before substitution, confirm pinout, timing, I2C speed support, operating voltage range, and interrupt/reset behavior to ensure compatibility.

Compliance and Environmental

• RoHS: RoHS compliant; Pb‑free (per NXP product information)
• Additional environmental or quality certifications: Not specified in datasheet

If your application requires specific environmental, safety, or reliability certifications, consult the latest NXP documentation or contact NXP support.

Detailed Specifications Summary

• Function: 2‑channel I2C‑bus switch / multiplexer with interrupt logic
• I2C speed: Up to 400 kHz (Standard/Fast‑mode)
• Supply voltage (VCC): 2.3 V to 5.5 V
• Address pins: 2 (A0, A1)
• Reset: Active‑low RESET input
• Interrupt: Upstream INT with per‑channel INT0/INT1
• Channels: 2 downstream channels
• Operating temperature: −40°C to +85°C
• Logic levels: I2C‑bus compatible
• Package code: PW (TSSOP‑14)
• Packaging: Tape & Reel (suffix ,118)
• Mounting type: Surface Mount
• Pin count: 14

Values not listed above are “Not specified in datasheet” in this overview. For exact limits and timing, use the official datasheet.

Frequently Asked Questions (FAQs)

• What is the operating supply range?

• 2.3 V to 5.5 V.

• What I2C speeds are supported?

• Standard‑ and Fast‑mode up to 400 kHz.

• How many address options are available?

• Two hardware address pins (A0, A1) allow up to four unique addresses.

• Does PCA9543APW,118 provide interrupt handling?

• Yes. It features interrupt logic with INT0/INT1 inputs (downstream) and an INT output (upstream).

• What does the “,118” suffix mean in PCA9543APW,118?

• It denotes Tape & Reel packaging for the PW (TSSOP‑14) package.

• What is the difference between PCA9543A and PCA9543?

• The “A” revision is the recommended version for I2C compliance and is generally the active, supported variant.

• Is there a SOIC version available?

• Yes, NXP offers the PCA9543AD,118 in an SOIC package (different footprint). Verify PCB layout before substitution.

Resources

• Datasheet: https://www.nxp.com/docs/en/data-sheet/PCA9543A.pdf
• Product page: https://www.nxp.com/products/interfaces/i2c-bus/ics/pca9543a-2-channel-i2c-bus-switch-with-interrupt-logic:PCA9543A

Summary for Engineers, Buyers, and Sourcing Teams

The NXP Semiconductors PCA9543APW,118 is a practical, low‑risk choice for I2C bus segmentation and address conflict management. With two controllable downstream channels, integrated interrupt aggregation, and a simple RESET mechanism, it offers robust control over multi‑device I2C architectures. Its operation from 2.3 V to 5.5 V and support up to 400 kHz cover a broad range of embedded systems, while the compact TSSOP‑14 package and tape‑and‑reel option streamline manufacturing. Active lifecycle status and RoHS compliance support long‑term availability and regulatory requirements.

When your design calls for cleanly partitioned I2C segments, straightforward interrupt handling, and scalable address mapping, the PCA9543APW,118 delivers an elegant solution backed by NXP’s extensive I2C portfolio and documentation.