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NXP Semiconductors PCA9541PW/03,112
- Part No.:
- PCA9541PW/03,112
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
PCA9541PW/03,112.pdf
- Description:
- IC INTERFACE SPECIALIZED 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,516
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Product details
Overview
PCA9541PW/03,112 from NXP Semiconductors is a 2-to-1 bidirectional I²C-bus master selector IC designed for high-reliability dual-master systems where uninterrupted operation is required during master failure or hot-swap maintenance. It features no-channel-selected-at-power-up behavior, active-low reset and interrupt logic, bus recovery initialization (9-clock pulse + NACK + STOP), and voltage-level translation across 1.8 V to 5 V domains. It enables failover control of shared downstream I²C slave devices in telecom infrastructure and industrial controllers.
For engineers reviewing the PCA9541PW/03,112 datasheet, PCA9541PW/03,112 pinout, PCA9541PW/03,112 application, or PCA9541PW/03,112 equivalent, key selection considerations include its power-up state (no channel selected), bus sensor interrupt behavior, dual-interrupt output routing (INT0/INT1), TSSOP16 package compatibility, and support for 400 kHz I²C operation with 6.0 V-tolerant I/O pins.
Technical Context
The PCA9541PW/03,112 implements a deterministic, non-arbitrated channel-switching mechanism controlled via I²C writes to per-master CONTROL registers, with switching triggered only on STOP condition receipt. Its internal bus sensor detects non-idle conditions during channel transitions and asserts BUSOK interrupt when external recovery is needed.
It integrates independent interrupt enable (IE) registers per master, supporting masking of BUSLOST, BUSOK, BUSINIT, and INT_IN events. The device uses an exclusive-OR logic relationship between MYBUS/NMYBUS bits to indicate bus ownership and between BUSON/NBUSON bits to determine connection state - both updated synchronously on STOP.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 2-to-1 bidirectional I²C-bus master selector with bus recovery and interrupt logic |
| Power-up state | No channel selected - either master can initiate control without prior arbitration |
| I²C clock frequency | 0 Hz to 400 kHz - supports standard and fast-mode I²C timing requirements |
| Voltage translation | 1.8 V / 2.5 V / 3.3 V ↔ 5 V - enables mixed-voltage I²C communication without level shifters |
| Supply voltage range | 2.3 V to 5.5 V - compatible with wide-range industrial and telecom power rails |
| I/O voltage tolerance | 6.0 V tolerant - allows safe interfacing with higher-voltage peripherals |
| ESD rating | 2000 V HBM, 200 V MM, 1000 V CDM - meets robustness requirements for board-level handling |
Pinout & Package
TSSOP16 package (SOT403-1), 4.4 mm body width, 16-pin surface-mount with exposed thermal pad on HVQFN variant (not applicable to PCA9541PW/03).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| INT0 | Active LOW interrupt output 0 | Signals bus ownership change or recovery completion to Master 0; requires external pull-up |
| SDA_MST0 | Serial data line for Master 0 | Bidirectional I²C data path; 6.0 V tolerant; requires external pull-up |
| SCL_MST0 | Serial clock line for Master 0 | Bidirectional I²C clock path; 6.0 V tolerant; requires external pull-up |
| RESET | Active LOW reset input | Resets I²C state machine and restores default register values; requires external pull-up |
| SCL_MST1 | Serial clock line for Master 1 | Bidirectional I²C clock path; 6.0 V tolerant; requires external pull-up |
| SDA_MST1 | Serial data line for Master 1 | Bidirectional I²C data path; 6.0 V tolerant; requires external pull-up |
| INT1 | Active LOW interrupt output 1 | Signals bus ownership change or recovery completion to Master 1; requires external pull-up |
| VSS | Supply ground | Reference for all internal circuitry; must be connected to system GND |
| A0–A3 | I²C slave address inputs | Hardware-configurable address bits; each tied HIGH/LOW to set unique 7-bit slave address |
| SCL_SLAVE | Downstream serial clock | Connects to shared slave-side I²C bus; 6.0 V tolerant; requires external pull-up |
| SDA_SLAVE | Downstream serial data | Connects to shared slave-side I²C bus; 6.0 V tolerant; requires external pull-up |
| INT_IN | Active LOW interrupt input | Propagates downstream interrupt events to upstream masters; requires external pull-up |
| VDD | Supply voltage | 2.3 V to 5.5 V operating rail; also sets max pass-gate voltage for level translation |
Key Features
| Feature | Design Value |
|---|---|
| No-channel-selected power-up | PCA9541PW/03 powers up with both upstream channels disabled - eliminates race conditions during cold start |
| Dual-interrupt output architecture | INT0 and INT1 provide independent, master-specific status signaling for failover coordination and diagnostics |
| Configurable bus recovery | Optional 9-clock + NACK + STOP sequence ensures downstream slaves enter known state before channel switch |
| Real-time bus traffic sensing | Detects non-idle conditions during switching and triggers BUSOK interrupt to request external recovery |
| Hardware address selection | Four address pins (A0–A3) allow up to 16 PCA9541PW/03 devices on same I²C bus without address conflict |
Applications
| Telecom Line Card Redundancy | Industrial PLC Dual-Controller Failover |
|---|---|
Use Scenario: Primary and backup controllers manage shared sensor/actuator I²C peripherals on a telecom line card; one controller may be removed for firmware update or hardware replacement. IC Role / Device Role / Timing Role: PCA9541PW/03 acts as a master gatekeeper, isolating failed or offline controller while enabling seamless handover to the active unit without bus contention. Use Value: Eliminates manual reset or power cycle of downstream slaves during controller switchover, preserving system uptime and reducing service interruption time. | Use Scenario: Two programmable logic controllers share access to temperature, pressure, and IO-expander I²C devices in a safety-critical manufacturing cell. IC Role / Device Role / Timing Role: PCA9541PW/03 enforces exclusive bus access using software-controlled channel selection and provides BUSLOST interrupts to notify inactive controller of handover. Use Value: Enables deterministic, software-managed redundancy without modifying slave firmware or adding arbitration logic to master controllers. |
| Server Baseboard Management (BMC) | Medical Diagnostic Equipment Hot-Swap Modules |
Use Scenario: A baseboard management controller (BMC) and host CPU both require access to power monitoring, fan control, and EEPROM I²C devices on a server motherboard. IC Role / Device Role / Timing Role: PCA9541PW/03 mediates I²C access between BMC and CPU, preventing simultaneous drive conflicts and supporting BMC-initiated resets during host boot sequences. Use Value: Allows BMC to perform full system health checks and configuration updates without requiring host CPU involvement or halting main application execution. | Use Scenario: Modular diagnostic modules (e.g., ECG, SpO₂) are inserted/removed while system remains powered; each module contains I²C sensors and calibration data. IC Role / Device Role / Timing Role: PCA9541PW/03 isolates disconnected modules from the main I²C bus and prevents bus lockup during hot-insertion using BUSOK-triggered recovery. Use Value: Guarantees bus integrity and avoids system-wide I²C hang during field-service operations, meeting IEC 62304 safety requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C master selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9541D/03 | SO16 package (3.9 mm width); identical electrical specs and register map; no thermal pad | Preferred for through-hole prototyping or legacy PCB layouts requiring SOIC footprint | Select PCA9541D/03 when board space permits larger SO16 or when thermal dissipation is not constrained |
| PCA9541BS/03 | HVQFN16 package (4 × 4 × 0.85 mm); includes exposed thermal pad; same logic and timing | Optimized for high-density, thermally demanding applications such as compact telecom modules | Choose PCA9541BS/03 when minimizing board area and enhancing thermal performance are critical design goals |
Compared with PCA9541D/03 and PCA9541BS/03, the PCA9541PW/03 offers the best balance of compactness (TSSOP16), manufacturability (lead-based solder compatibility), and thermal performance - making it ideal for volume production of mid-density embedded systems where reflow profile control and assembly yield are prioritized.
Availability
PCA9541PW/03,112 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and medical diagnostic equipment requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.
Supply support for PCA9541PW/03,112 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.
The PCA9541 product line was developed to solve deterministic I²C bus sharing in fault-tolerant dual-master systems, targeting telecom base stations, industrial automation controllers, and high-availability server management subsystems.
FAQ
What is the power-up behavior difference between PCA9541PW/03,112 and PCA9541PW/01,112?
The PCA9541PW/03,112 powers up with no channel selected - both upstream masters remain isolated until explicit I²C command initiates control. In contrast, PCA9541PW/01,112 powers up with Channel 0 (Master 0) automatically enabled. This makes PCA9541PW/03,112 safer for systems where uncontrolled bus access at startup could cause contention or unintended peripheral activation. The PCA9541PW/03,112's neutral start state requires deliberate software action before any master engages the downstream bus.
Does PCA9541PW/03,112 support hot insertion of master controllers?
Yes, PCA9541PW/03,112 supports hot insertion: its active-low RESET pin allows full initialization after controller insertion, and the bus sensor detects non-idle conditions to trigger BUSOK interrupt if switching occurs mid-transaction. The device does not rely on power-on reset alone - software can assert RESET at any time to reinitialize state machines and clear pending interrupts. This ensures predictable behavior when a backup master is plugged into a live system, and the PCA9541PW/03,112 maintains isolation until explicitly commanded to connect.
How does the bus recovery function operate in PCA9541PW/03,112?
When BUSINIT = 1 is written to the CONTROL register, PCA9541PW/03,112 executes a defined recovery sequence before connecting the new master: it sends nine SCL_SLAVE clock pulses while holding SDA_SLAVE high (equivalent to eight data bits + NACK), then issues a STOP condition. This forces downstream slaves to abort pending transactions and return to idle state. Upon completion, PCA9541PW/03,112 asserts the appropriate INT0 or INT1 line and sets the BUSINIT bit in the Interrupt Status Register - confirming readiness for safe channel handover.
Can PCA9541PW/03,112 interface 1.8 V masters with 5 V slaves?
Yes, PCA9541PW/03,112 enables direct voltage-level translation between 1.8 V, 2.5 V, 3.3 V, and 5 V I²C domains. Its pass-gate structure uses VDD as the reference for maximum passed voltage - so with VDD = 1.8 V, only signals ≤1.8 V pass to the slave side; with VDD = 5 V, signals up to 5 V pass. This eliminates external level shifters. All I/O pins are 6.0 V tolerant, and the PCA9541PW/03,112 maintains signal integrity across combinations like 1.8 V SCL_MST0/SDA_MST0 driving 5 V SCL_SLAVE/SDA_SLAVE when VDD = 5 V.
What interrupt sources does PCA9541PW/03,112 support, and how are they masked?
PCA9541PW/03,112 supports four maskable interrupt sources per master: BUSLOST (loss of bus control), BUSOK (non-idle switch detected), BUSINIT (recovery sequence complete), and INT_IN (downstream interrupt propagation). Masking is controlled via the 4-bit IE register (bits BUSLOSTMSK, BUSOKMSK, BUSINITMSK, INTINMSK), where logic 1 disables the corresponding interrupt output. Each master has its own IE register, allowing independent interrupt policy - e.g., Master 0 may mask BUSOK while Master 1 receives it - ensuring flexible system-level error handling without cross-master interference.
PCA9541PW/03,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Applications:
- 2-Channel I2C Multiplexer
- Interface:
- I2C, SMBus
- Voltage - Supply:
- 2.3V ~ 5.5V
- Supplier Device Package:
- 16-TSSOP
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
PCA9541PW/03,112 FAQ
1.How can I place an order for PCA9541PW/03,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9541PW/03,112 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for PCA9541PW/03,112 reliable?
The price and inventory of PCA9541PW/03,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9541PW/03,112 is usually 5 days.
3.What payment methods are accepted for PCA9541PW/03,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9541PW/03,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9541PW/03,112?
PCA9541PW/03,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9541PW/03,112 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for PCA9541PW/03,112?
For technical support, including PCA9541PW/03,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9541PW/03,112 requirements.
6.How does Aetrix verify that PCA9541PW/03,112 is sourced from the original manufacturer or authorized distributors?
All PCA9541PW/03,112 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PCA9541PW/03,112 meets industry standards.
7.What is the process for return or replacement of PCA9541PW/03,112?
All PCA9541PW/03,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9541PW/03,112, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The PCA9541PW/03,112 part is unused and in its original packaging.
Return procedure for PCA9541PW/03,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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