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NXP Semiconductors PCA9541D/01,112
- Part No.:
- PCA9541D/01,112
- Manufacturer:
- NXP Semiconductors
- Category:
- Specialized
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
PCA9541D/01,112.pdf
- Description:
- IC INTERFACE SPECIALIZED 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,166
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Product details
Overview
PCA9541D/01 from NXP Semiconductors is a 2-to-1 I²C-bus master selector IC designed for high-reliability dual-master systems, enabling failover between primary and backup controllers without bus interruption. It features channel 0 pre-selected at power-up, 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 is used in telecom line cards requiring hot-swap-capable redundancy.
For engineers reviewing the PCA9541D/01 datasheet, PCA9541D/01 pinout, PCA9541D/01 application, or PCA9541D/01 equivalent, key selection criteria include its SO16 package, default Channel-0 startup behavior, bidirectional I²C switching with bus sensor and recovery, and compatibility with SMBus standards up to 400 kHz.
Technical Context
The PCA9541D/01 implements a state-machine–driven channel arbitration architecture with no hardware arbitration logic-masters gain control via software writes to dedicated CONTROL registers followed by STOP commands. Its internal bus sensor detects non-idle conditions during channel switching and triggers BUSOK interrupts when external recovery is required.
It supports independent interrupt masking per master via IE registers, enables bus initialization/recovery on demand (BUSINIT=1), and uses exclusive-OR logic between MYBUS/NMYBUS and BUSON/NBUSON bits to determine channel ownership and connection state-ensuring deterministic, non-arbitrated master handover.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 2-to-1 bidirectional I²C-bus master selector with interrupt logic and reset |
| Startup Behavior | Channel 0 selected automatically at power-on (PCA9541/01 variant) |
| Supply Voltage | 2.3 V to 5.5 V - supports mixed-voltage I²C domains including 1.8 V, 2.5 V, 3.3 V, and 5 V |
| I²C Clock Frequency | 0 Hz to 400 kHz - compatible with standard and fast-mode I²C |
| Interrupt Logic | Active-low INT0 and INT1 outputs plus active-low INT_IN input with maskable BUSLOST/BUSOK/BUSINIT events |
| Addressing | 4 hardware-selectable address pins (A0–A3) - supports up to 16 devices on same I²C bus |
| ESD Protection | 2000 V HBM, 200 V MM, 1000 V CDM - meets industrial reliability requirements |
Pinout & Package
PCA9541D/01 is supplied in a plastic small outline package (SO16) with 16 leads and 3.9 mm body width (SOT109-1). All I/O pins are 6.0 V tolerant; external pull-up resistors required on all SCL/SDA lines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| INT0 | Active-low interrupt output 0 | Signals bus ownership change or recovery completion to Master 0 |
| SDA_MST0 | Serial data line for Master 0 | Bidirectional I²C data path; requires external pull-up |
| SCL_MST0 | Serial clock line for Master 0 | Bidirectional I²C clock path; requires external pull-up |
| RESET | Active-low reset input | Resets internal state machine and restores default configuration |
| SCL_MST1 | Serial clock line for Master 1 | Bidirectional I²C clock path; requires external pull-up |
| SDA_MST1 | Serial data line for Master 1 | Bidirectional I²C data path; requires external pull-up |
| INT1 | Active-low interrupt output 1 | Signals bus ownership change or recovery completion to Master 1 |
| VSS | Supply ground | Reference for all signals and internal logic; must be connected |
| A0–A3 | Hardware address inputs | Set unique I²C slave address; externally pulled to VDD or VSS |
| SCL_SLAVE | Downstream serial clock | Connects to shared slave I²C bus; requires external pull-up |
| SDA_SLAVE | Downstream serial data | Connects to shared slave I²C bus; requires external pull-up |
| INT_IN | Active-low interrupt input | Propagates downstream interrupt events to both upstream masters when enabled |
| VDD | Supply voltage | 2.3 V to 5.5 V power source; also sets maximum pass-gate voltage level |
Key Features
| Feature | Design Value |
|---|---|
| Channel Selection | Software-controlled via I²C write to CONTROL register, with automatic channel switch triggered only on STOP command |
| Bus Recovery | Integrated 9-clock + NACK + STOP sequence initializes downstream slaves before channel handover - eliminates need for hardware reset |
| Voltage Translation | Pass-gate architecture allows 1.8 V/2.5 V/3.3 V masters to communicate with 5 V slaves without external level shifters |
| Hot Insertion Support | Robust power-up sequencing and no-glitch operation enable safe insertion/removal of controller cards in live systems |
| Interrupt Flexibility | Dedicated INT0/INT1 outputs per master plus INT_IN input allow coordinated fault signaling across redundant control paths |
Applications
| Telecom Line Cards | Industrial PLC Backplanes |
|---|---|
Use Scenario: Dual-controller redundancy in carrier-grade access equipment where primary controller failure must not disrupt service. IC Role / Device Role / Timing Role: Gatekeeper multiplexer that isolates failed master and transfers full I²C bus control to backup controller within milliseconds. Use Value: Enables zero-downtime maintenance and hot-swap capability while preserving communication with downstream sensors, DACs, and PMUs. |
Use Scenario: Modular I/O backplane with interchangeable CPU modules sharing common fieldbus peripherals. IC Role / Device Role / Timing Role: Bus arbiter ensuring only one CPU module accesses shared I²C slave devices (e.g., temperature monitors, EEPROMs) at any time. Use Value: Prevents bus contention and data corruption during module replacement or firmware update cycles. |
| Medical Diagnostic Systems | Avionics Data Concentrators |
Use Scenario: Redundant imaging subsystems requiring synchronized access to calibration EEPROMs and sensor arrays. IC Role / Device Role / Timing Role: Fail-safe I²C master selector that maintains uninterrupted communication with critical calibration memory and ADCs. Use Value: Guarantees deterministic bus recovery after controller reset, meeting IEC 62304 safety-critical timing requirements. |
Use Scenario: Multi-processor avionics units where LRUs share sensor buses but require strict isolation during self-test or reconfiguration. IC Role / Device Role / Timing Role: Isolation enforcer that electrically separates master domains while propagating status via INT_IN/INT0/INT1 signals. Use Value: Supports DO-254-compliant partitioning by preventing cross-domain interference during BIT execution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I²C master selector applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TCA9544APWR | 4-channel I²C switch without bus recovery, interrupt logic, or reset; no channel pre-selection at startup | Lacks failover coordination and bus initialization - suitable only for static channel routing | Select when multi-drop routing is needed without redundancy or recovery requirements |
| PCA9548ADPW | 8-channel I²C switch with no interrupt outputs, no reset pin, and no bus sensor or recovery function | Designed for expansion, not redundancy - cannot detect or recover from mid-transaction channel switches | Choose for high-port-count fanout where master arbitration is handled externally |
Compared with TCA9544APWR and PCA9548ADPW, the PCA9541D/01 uniquely delivers integrated bus recovery, deterministic master handover via STOP-triggered switching, and dual-interrupt signaling essential for high-availability dual-master architectures - making it irreplaceable where system uptime and fault containment are mandatory.
Availability
PCA9541D/01 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and medical diagnostics requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for PCA9541D/01 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 PCA9541D/01 belongs to NXP's I²C-bus interface portfolio, engineered specifically for fault-tolerant dual-master systems where continuous bus operation during controller maintenance or failure is non-negotiable.
FAQ
What is the default channel selection behavior of PCA9541D/01 at power-up?
The PCA9541D/01 powers up with Channel 0 selected by default, as defined by its /01 variant designation. This ensures immediate operational readiness of the primary master without requiring initial I²C configuration. The internal Power-On Reset (POR) circuit configures the device to this state, and the RESET pin provides identical initialization on demand. This behavior distinguishes PCA9541D/01 from the /03 variant, which starts with no channel selected.
How does PCA9541D/01 handle bus recovery during a channel switch?
The PCA9541D/01 performs an integrated bus recovery sequence when BUSINIT=1 is written to its CONTROL register: it sends nine SCL pulses, releases SDA_SLAVE (equivalent to a NACK), then issues a STOP condition on the downstream bus. This clears pending transactions and resets slave states before connecting the new master. The PCA9541D/01 asserts INT0 or INT1 upon completion, confirming successful initialization prior to handover.
Can PCA9541D/01 translate voltage levels between different I²C domains?
Yes, the PCA9541D/01 uses pass-gate switches whose maximum passed voltage is limited by the VDD pin voltage. This allows direct interfacing between 1.8 V, 2.5 V, 3.3 V, and 5 V I²C domains without external level shifters. For example, a 3.3 V master on SCL_MST0/SDA_MST0 can safely communicate with 5 V slaves on SCL_SLAVE/SDA_SLAVE when VDD = 5 V, with all I/O pins rated for 6.0 V tolerance.
What is the role of the INT_IN pin on PCA9541D/01?
The INT_IN pin on PCA9541D/01 is an active-low interrupt input that collects asynchronous interrupt signals from downstream slave devices. When enabled via the INTINMSK bit in the IE register, it propagates those events to both upstream masters through INT0 and INT1 outputs. This enables centralized fault reporting across redundant controllers - for instance, a thermal shutdown alert from a downstream sensor can trigger coordinated response from either master.
Does PCA9541D/01 support hot insertion and removal in live systems?
Yes, PCA9541D/01 supports hot insertion due to its no-glitch power-up behavior, robust internal POR, and ability to isolate failed masters without disrupting downstream communication. Its low standby current and 6.0 V-tolerant I/O pins ensure safe connection/disconnection while the system remains powered. This makes PCA9541D/01 suitable for carrier-class line cards and modular industrial controllers requiring field-replaceable units without system shutdown.
PCA9541D/01,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Applications:
- 2-Channel I2C Multiplexer
- Interface:
- I2C, SMBus
- Voltage - Supply:
- 2.3V ~ 5.5V
- Supplier Device Package:
- 16-SO
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
PCA9541D/01,112 FAQ
1.How can I place an order for PCA9541D/01,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for PCA9541D/01,112 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 PCA9541D/01,112 reliable?
The price and inventory of PCA9541D/01,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PCA9541D/01,112 is usually 5 days.
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PCA9541D/01,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your PCA9541D/01,112 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 PCA9541D/01,112?
For technical support, including PCA9541D/01,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PCA9541D/01,112 requirements.
6.How does Aetrix verify that PCA9541D/01,112 is sourced from the original manufacturer or authorized distributors?
All PCA9541D/01,112 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 PCA9541D/01,112 meets industry standards.
7.What is the process for return or replacement of PCA9541D/01,112?
All PCA9541D/01,112 units undergo pre-shipment inspection (PSI). If there is an issue with PCA9541D/01,112, 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 PCA9541D/01,112 part is unused and in its original packaging.
Return procedure for PCA9541D/01,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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