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NXP Semiconductors PCA9541PW/03,118
- Part No.:
- PCA9541PW/03,118
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
PCA9541PW/03,118.pdf
- Description:
- IC INTERFACE SPECIALIZED 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,706
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Product details
Overview
PCA9541PW/03,118 from NXP Semiconductors is a 2-to-1 bidirectional I²C-bus master selector IC designed for high-reliability dual-master systems where uninterrupted slave access must be maintained during master failure or hot-swap maintenance. It features no-channel-selected power-up behavior, active-low reset and interrupt logic, bus recovery initialization (9-clock + NACK + STOP), and voltage-level translation across 1.8 V to 5 V domains. It enables failover control in redundant controller architectures such as industrial PLC backplanes and telecom line cards.
For engineers reviewing the PCA9541PW/03,118 datasheet, PCA9541PW/03,118 pinout, PCA9541PW/03,118 application, or PCA9541PW/03,118 equivalent, key selection criteria include its /03 variant's unselected-startup behavior, dual-interrupt signaling (INT0/INT1), bus traffic sensing without recovery mode, 4-bit hardware addressability, and TSSOP16 package compatibility with 2.3 V–5.5 V operation.
Technical Context
The PCA9541PW/03 implements a deterministic, non-arbitrated channel-switching mechanism controlled via I²C writes to per-master CONTROL registers (Reg#01), where MYBUS/NMYBUS and BUSON/NBUSON bits define bus ownership and connection state using XOR logic. Switching occurs only on receipt of a STOP condition from the requesting master, ensuring atomicity and preventing mid-transaction disruption.
Its bus recovery function-activated by setting BUSINIT=1-asserts nine SCL_SLAVE clock pulses, releases SDA_SLAVE (emulating NACK), then issues a STOP to initialize downstream slaves lacking hardware reset. Concurrently, the internal bus sensor detects non-idle conditions during switching and triggers BUSOK interrupts when recovery is bypassed, requiring external software-initiated recovery.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 2-to-1 bidirectional I²C-bus master selector with interrupt logic and reset |
| Power supply range | 2.3 V to 5.5 V - supports mixed-voltage system integration without level shifters |
| I²C clock frequency | 0 Hz to 400 kHz - compatible with standard-mode and fast-mode I²C buses |
| Input tolerance | 6.0 V tolerant on all I/O pins - enables safe interfacing with 5 V masters/slaves even at lower VDD |
| Startup behavior | No channel selected at power-on - allows either master to initiate control without pre-assigned priority |
| Address inputs | 4 hardware-selectable address pins (A0–A3) - supports up to 16 devices on same I²C bus |
| ESD rating | 2000 V HBM, 200 V MM, 1000 V CDM - meets industrial robustness requirements |
Pinout & Package
TSSOP16 package (SOT403-1), 4.4 mm body width, 0.65 mm lead pitch, exposed pad not present - suitable for space-constrained PCB layouts with standard reflow profiles.
| 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 interface; 6 V tolerant, requires external pull-up |
| SCL_MST0 | Serial clock line for Master 0 | Bidirectional I²C clock interface; 6 V tolerant, requires external pull-up |
| RESET | Active LOW reset input | Resets internal state machine and restores default register values; requires external pull-up |
| SCL_MST1 | Serial clock line for Master 1 | Bidirectional I²C clock interface; 6 V tolerant, requires external pull-up |
| SDA_MST1 | Serial data line for Master 1 | Bidirectional I²C data interface; 6 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 digital and analog circuitry; must be low-impedance connection |
| A0–A3 | Hardware address inputs | Set device I²C slave address (7-bit); each tied to VSS or VDD to configure unique bus address |
| SCL_SLAVE | Downstream serial clock | Connects to shared slave-side I²C bus; passes clock signals bidirectionally when channel enabled |
| SDA_SLAVE | Downstream serial data | Connects to shared slave-side I²C bus; passes data signals bidirectionally when channel enabled |
| INT_IN | Active LOW interrupt input | Propagates downstream interrupt events to both upstream masters when enabled; requires external pull-up |
| VDD | Supply voltage | Primary power rail (2.3–5.5 V); also sets maximum pass-gate voltage for level translation |
Key Features
| Feature | Design Value |
|---|---|
| No-channel-selected startup | PCA9541PW/03 powers up with neither master connected - eliminates priority bias and enables symmetric failover initiation |
| Bus recovery initialization | Generates standardized 9-clock + NACK + STOP sequence to reset downstream slaves lacking hardware reset pins |
| Bus traffic sensor | Detects non-idle SCL/SDA activity during channel switch and asserts BUSOK interrupt - flags need for external recovery |
| Voltage-level translation | VDD-limited pass gates allow 1.8 V/2.5 V/3.3 V masters to communicate with 5 V slaves without external translators |
| Hot-insertion support | Robust power sequencing and glitch-free startup enable safe insertion/removal of controller cards in live backplanes |
| Independent per-master registers | Dual IE and CONTROL register banks (Master 0 and Master 1) prevent cross-talk and enable autonomous bus arbitration |
Applications
| Redundant Controller Backplane | Telecom Line Card Failover |
|---|---|
|
Use Scenario: Dual-controller architecture in industrial PLC chassis where primary controller handles real-time I/O while backup remains idle until fault detection. IC Role / Device Role / Timing Role: PCA9541PW/03 acts as master gatekeeper, isolating failed controller and enabling seamless handover to backup without slave bus corruption. Use Value: Eliminates manual intervention during controller failure; maintains continuous slave communication via automatic bus recovery and interrupt-driven status reporting. |
Use Scenario: Carrier-grade line card with primary and standby processors sharing access to common PHY, EEPROM, and temperature sensors. IC Role / Device Role / Timing Role: PCA9541PW/03 mediates I²C access between two ARM-based processors and shared peripherals, enforcing exclusive bus ownership. Use Value: Enables zero-downtime switchover during firmware updates or processor resets, verified by BUSINIT completion interrupt and BUSLOST notification. |
| Server Management Controller Sharing | Automotive Domain Controller Redundancy |
|
Use Scenario: BMC (Baseboard Management Controller) and host CPU in enterprise server sharing access to PMBus-configurable VRMs and thermal sensors. IC Role / Device Role / Timing Role: PCA9541PW/03 serves as intelligent I²C multiplexer, allowing BMC to monitor power delivery during boot while CPU assumes control post-boot. Use Value: Prevents I²C bus contention during boot transition; supports dynamic role assignment via software-controlled channel selection and RESET synchronization. |
Use Scenario: Dual-zone domain controller in ADAS ECU where safety-critical and infotainment subsystems require isolated but coordinated access to shared CAN transceivers and flash memory. IC Role / Device Role / Timing Role: PCA9541PW/03 provides fail-safe I²C path selection between ASIL-B and QM masters, with BUSOK interrupt triggering diagnostic recovery routines. Use Value: Meets ISO 26262 functional safety requirements by detecting bus collisions and enabling deterministic recovery before safety violation escalation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C master selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9544APW,118 | 4-channel I²C switch with identical /03 startup behavior; lacks bus recovery and traffic sensor logic | Used where >2 masters require time-multiplexed access, not failover redundancy | Select PCA9541PW/03,118 when dual-master failover, bus initialization, and interrupt-driven recovery are required |
| TCA9544APWR | TI's pin-compatible 4-channel version; supports higher 1 MHz clock rate but no BUSINIT or BUSOK functionality | Preferred in high-throughput multi-peripheral routing, not high-availability master handover | Choose PCA9541PW/03,118 for mission-critical redundancy where guaranteed bus initialization and traffic-aware switching are mandatory |
Compared with PCA9544APW,118 and TCA9544APWR, the PCA9541PW/03,118 uniquely delivers deterministic dual-master failover with built-in bus recovery and real-time traffic monitoring - making it irreplaceable in systems where slave device state consistency must survive master transitions without external intervention.
Availability
PCA9541PW/03,118 is available at Aetrix Electronics and suitable for industrial automation backplanes, telecom line cards, and automotive domain controllers requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for PCA9541PW/03,118 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 leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in I²C, SMBus, and system-level bus management ICs.
The PCA9541 product line was engineered specifically for high-availability dual-master I²C systems requiring deterministic failover, bus state recovery, and voltage-domain interoperability - addressing gaps in legacy multiplexers lacking interrupt-aware control logic.
FAQ
What distinguishes PCA9541PW/03,118 from the PCA9541PW/01,118 variant?
The PCA9541PW/03,118 powers up with no channel selected, allowing either master to assert control immediately after power-on or reset. In contrast, PCA9541PW/01,118 defaults to Channel 0 (Master 0) at startup. This makes PCA9541PW/03,118 ideal for symmetric redundancy systems where neither master has inherent priority - a critical distinction confirmed in NXP's ordering information table and functional description section.
How does the bus recovery function operate in PCA9541PW/03,118?
When BUSINIT=1 is written to the CONTROL register, PCA9541PW/03,118 executes a defined recovery sequence on SCL_SLAVE and SDA_SLAVE: nine clock pulses, release of SDA_SLAVE (simulating NACK), then a STOP condition. This resets downstream slaves lacking hardware reset, ensuring clean transaction termination before channel handover - a feature explicitly documented in Section 8.3 and Figure 1 of the datasheet.
Can PCA9541PW/03,118 interface between 3.3 V masters and 5 V slaves?
Yes. The pass-gate architecture ties maximum passed voltage to VDD. With VDD = 3.3 V, PCA9541PW/03,118 safely translates signals from 3.3 V masters to 5 V slaves without damage or level-shifter components. This voltage translation capability is specified in the General Description and confirmed in the Features section under "Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses."
What is the purpose of the BUSOK interrupt in PCA9541PW/03,118?
The BUSOK interrupt signals that PCA9541PW/03,118 detected non-idle bus activity (SCL/SDA not both HIGH) during a channel switch when bus recovery was disabled (BUSINIT=0). It alerts the new master that external software recovery is required - a design-specific behavior documented in Section 8.3 and Table 6 (BUSOKMSK bit description) of the datasheet.
Does PCA9541PW/03,118 support hot insertion in live backplane systems?
Yes. PCA9541PW/03,118 includes no-glitch power-up behavior, active-low RESET with internal POR, and robust ESD protection (2000 V HBM), enabling safe insertion into powered systems. Its ability to isolate failed masters and recover bus state without disrupting downstream slaves makes it qualified for hot-swap applications - explicitly cited in Section 2 "Features and benefits" and Section 3 "Applications."
PCA9541PW/03,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- 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/03,118 FAQ
1.How can I place an order for PCA9541PW/03,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9541PW/03,118 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/03,118 reliable?
The price and inventory of PCA9541PW/03,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9541PW/03,118 is usually 5 days.
3.What payment methods are accepted for PCA9541PW/03,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PCA9541PW/03,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for PCA9541PW/03,118?
PCA9541PW/03,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9541PW/03,118 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/03,118?
For technical support, including PCA9541PW/03,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9541PW/03,118 requirements.
6.How does Aetrix verify that PCA9541PW/03,118 is sourced from the original manufacturer or authorized distributors?
All PCA9541PW/03,118 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/03,118 meets industry standards.
7.What is the process for return or replacement of PCA9541PW/03,118?
All PCA9541PW/03,118 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9541PW/03,118, 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/03,118 part is unused and in its original packaging.
Return procedure for PCA9541PW/03,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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