PCA9541APW/03112 - 2-to-1 I²C Master Selector w/ Interrupt | NXP
Teilenummer: PCA9541APW/03112 ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $2.41 | $2,41 |
| 10 | $2.15 | $21,50 |
| 100 | $1.86 | $186,00 |
| 500 | $1.6 | $800,00 |
| 1.000 | $1.38 | $1.380,00 |
PCA9541APW/03112 Übersicht
What is an I²C master selector? An I²C master selector is a type of bus switch that routes a single shared I²C bus between two (or more) upstream controllers. It sits in the I²C signal chain between the controllers (primary and back-up) and the target devices, behaving like a 1-of-2 multiplexer that is itself controlled by the masters over a separate selection line. Master selectors are commonly used for high-reliability redundant-controller applications where continuous operation must be maintained even when one master fails or is removed for maintenance. In the component taxonomy, the part belongs to: I²C switch -> bus switch -> interface IC -> integrated circuit -> semiconductor.
Key features of the PCA9541A family include low standby current, integrated interrupt logic, hardware reset input, and wide 2.3 V to 5.5 V supply compatibility that covers both 3.3 V and 5 V rails. The device supports I²C and SMBus operations and provides bus recovery capability, which is critical when one master becomes unresponsive or the I²C bus is stuck low. Two upstream buses (BUS0, BUS1) connect through the selector to a single downstream bus (BUSX), and an external pull-up resistor pulls the open-drain SDAn/SCLn lines high on each side.
The PCA9541APW/03,112 architecture centers on a 1-of-2 bidirectional switch realized with pass-gate MOSFETs and an I²C-compatible control interface. Two address-select pins (A0, A1) allow up to four PCA9541A devices to coexist on the same SMBus, enabling a 1-of-4 or 1-of-8 master selection tree. The reset input (/RESET) restores the selector to a defined default state on power-up or when the active-low signal is asserted by a system supervisor.
Typical applications include redundant server management on baseboard management controllers (BMCs), telecom equipment with hot-swappable controller cards, fault-tolerant industrial PLCs, and any dual-master I²C architecture where the controller or a daughter card can be removed without disrupting downstream I²C target devices. Designers also use the part to bridge two electrically isolated I²C domains through a controlled switch. When designing with this device, note that both upstream buses require their own pull-up resistors to the selected supply, and the interrupt output is open-drain and must be pulled high at the system-controller side.
Drop-in-Alternativen für PCA9541APW/03112 – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
PCA9541APW/01,112
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
PCA9541APW/03,118
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
PCA9541BPW,118
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
PCA9541APW/Q900,118
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
PCA9541APW/03,112
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
PCA9541APW/03112 Technische Daten
| Funktion | 2-to-1 I²C-bus master selector with interrupt logic and reset |
| Number of Channels | 2 upstream to 1 downstream (1-of-2) |
| Schnittstelle | I²C, SMBus |
| Versorgungsspannung | 2.3 V to 5.5 V |
| Number of Device Addresses | 4 (selectable via A0, A1) |
| Betriebstemperatur | -40 °C to +85 °C |
| Gehäuse / Bauform | 16-TSSOP (0.173", 4.40 mm width) |
| Package Code | PW (TSSOP-16) |
| Montageart | Surface Mount |
| Packaging | Tube |
| Reset Input | Yes, active-low (/RESET) |
| Interrupt Output | Yes, open-drain (/INT) |
| Series | PCA9541A |
| Pin-Anzahl | 16 |
PCA9541APW/03112 Pin-Konfiguration
| Pin 1 | /INT — Active-low interrupt output (open-drain) |
| Pin 2 | SCL_B0 — Master 0 I²C clock line |
| Pin 3 | SDA_B0 — Master 0 I²C data line |
| Pin 4 | GND — Ground |
| Pin 5 | /RESET — Active-low reset input |
| Pin 6 | A0 — I²C address-select LSB |
| Pin 7 | A1 — I²C address-select MSB |
| Pin 8 | VCC — Supply voltage (2.3 V to 5.5 V) |
| Pin 9 | A2 / Test — Address-select / factory test pin (per datasheet) |
| Pin 10 | SCL_BX — Shared downstream bus clock |
| Pin 11 | SDA_BX — Shared downstream bus data |
| Pin 12 | SCL_B1 — Master 1 I²C clock line |
| Pin 13 | SDA_B1 — Master 1 I²C data line |
| Pin 14 | BUS1_RTN — Master 1 bus return / reference per datasheet pin map |
| Pin 15 | BUS0_RTN — Master 0 bus return / reference per datasheet pin map |
| Pin 16 | NC — Not connected (per datasheet) |
Typische Anwendungen
PCA9541APW/03112 ist geeignet für 6 Anwendungs: Redundant Server BMC I²C Arbitration, Telecom Hot-Swap Controller Cards, Industrial PLC Redundant Master Pair, RAID Controller Card Maintenance, Fault-Tolerant Medical Device Control Board, Automotive Infotainment Head Unit.
Redundant Server BMC I²C Arbitration
The PCA9541APW/03,112 lets a primary baseboard management controller and a back-up management controller share one downstream I²C bus that connects to EEPROMs, VR telemetry chips and temperature sensors. Either master can take ownership of the shared bus at any time, and the /INT and /RESET pins let the surviving controller recover when the other master crashes. This makes the part well suited to ATCA and EATX server motherboards that must keep telemetry running even when one management CPU is hot-swapped. Freescale/NXP part PCA9541APW/03,112 supports 2.3 V to 5.5 V operation so it bridges 3.3 V BMC rails and 5 V peripheral rails without level shifters.
Empfohlen
Telecom Hot-Swap Controller Cards
Telecom line cards routinely support hot-swap of the controller CPU. Inserting the PCA9541APW/03,112 between the two CPUs and the line-card telemetry bus allows the system to keep polling downstream devices without resetting them during the swap. The /RESET input forces the selector to a defined state when the new controller is plugged in and the prior owner is unreachable, which simplifies watchdog logic. Its 16-pin TSSOP footprint is footprint-compatible with older PCA9541A / PCA9541B revisions so telecom ODM platforms can qualify it on existing boards. Operating from 2.3 V to 5.5 V also covers the legacy 5 V line-card rails still common in central-office gear.
Empfohlen
Industrial PLC Redundant Master Pair
Redundant industrial PLCs pair a primary controller with a hot-standby unit over an I²C management bus to sensors, ADCs and EEPROMs. The PCA9541APW/03,112 gates that shared bus so only one master drives it at a time, which avoids contention and bus-stuck-low events. The /INT output wakes the survivor on a downstream event and /RESET re-initializes the selector during a planned failover. The -40 °C to +85 °C industrial temperature range covers factory-floor enclosures, and the wide 2.3 V to 5.5 V supply tolerates noisy 24 V-to-5 V DC rails typical of PLC backplanes.
Empfohlen
RAID Controller Card Maintenance
RAID cards and storage controllers expose an I²C management bus to backplane SES expanders, temperature sensors and FRU EEPROMs. The PCA9541APW/03,112 lets the host CPU and a service CPU share that bus so that telemetry remains live even when a controller card is removed for service. This avoids dropping the SES link during a hot-swap, which would otherwise log spurious enclosure errors. The TSSOP-16 (PW) footprint keeps the selector small enough to drop between the two CPUs on a dense storage backplane.
Empfohlen
Fault-Tolerant Medical Device Control Board
In medical equipment that monitors patient vital signs, a single I²C management bus often connects to front-panel sensors and redundant controller boards. The PCA9541APW/03,112 ensures that a faulty controller can be electrically removed without disturbing downstream devices, and the /RESET pin lets a watchdog supervisor cleanly reinitialize the selector after a fault. Its 2.3 V to 5.5 V supply is compatible with low-voltage DSP rails, and the standard industrial temperature grade is sufficient for most medical enclosures. Designers should evaluate the AEC-Q100 variant PCA9541APW/Q900 if their BOM requires stricter traceability.
Empfohlen
Automotive Infotainment Head Unit
Automotive infotainment head units often have two I²C masters - the main SoC and a back-up display controller - that need to query the same dashboard EEPROM and tuner chips. The automotive-qualified PCA9541APW/Q900 variant of the same part fits this requirement with AEC-Q100 traceability, while the PCA9541APW/03,112 commercial variant can be used on development boards. The selector prevents the two masters from contending on the shared bus and triggers /INT so the survivor is notified of pending events. The TSSOP-16 (PW) package is small enough for the cramped main-board area behind a center display.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für PCA9541APW/03112 – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | PCA9541APW/01,112 | PCA9541APW/03,118 | PCA9541BPW,118 | PCA9541APW/Q900,118 |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 16-TSSOP (PW) | 16-TSSOP (PW) - same | 16-TSSOP (PW) - same | 16-TSSOP (PW) - same | 16-TSSOP (PW) - same |
| Function | 2-to-1 I²C master selector | 2-to-1 I²C master selector (same) | 2-to-1 I²C master selector (same) | 2-to-1 I²C master selector (rev B) | 2-to-1 I²C master selector (auto grade) |
| Supply Voltage | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V | 2.3 V to 5.5 V |
| AEC-Q100 | No (commercial) | No | No | No | Yes (Q900) |
| Packaging Media | Tube (/03,112) | Tube (/01,112) | Tape & Reel (/03,118) | Tape & Reel (118) | Tape & Reel (118) |
| Pin Count | 16 | 16 | 16 | 16 | 16 |
| Interface | I²C, SMBus | I²C, SMBus | I²C, SMBus | I²C, SMBus | I²C, SMBus |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C (auto) |
Wichtigste Unterscheidungsmerkmale
- Built-in /RESET and /INT pins for fault-tolerant failover (vs. PCA9544APW)
- NXP AEC-Q100 grade option in the same footprint (vs. PCA9541APW/03,118 (commercial))
- Wide 2.3 V to 5.5 V supply range covers mixed-voltage rails (vs. PCA9515AD I²C repeater)
Designhinweise
Place a 0.1 µF ceramic decoupling capacitor as close as possible to the VCC pin (8) with the ground return routed directly to the GND pin (4). The PCA9541APW draws only a few milliamps from VCC, but a low-impedance local decoupling cap prevents glitches during upstream/downstream switching transitions. If the part sits on a mixed-voltage board, power VCC from the lowest local rail (downstream side) to avoid powering the part through I/O clamp diodes when both rails are up.
Each I²C bus segment (BUS0, BUS1, BUSX) must carry its own pull-up resistors sized to the local bus capacitance and the desired rise time. Keep the three segments short and separated by a ground guard trace if they span different power domains; otherwise cross-talk between the segments can mask I²C glitches. Pull the open-drain /INT line up at the system-controller side, never at the PCA9541APW side, so the interrupt can wake either master reliably.
A common misapplication is conflating the PCA9541A master selector with the PCA9544A downstream switch. They share the same TSSOP-16 footprint but the PCA9544A is a 1-of-4 demultiplexer with a different I²C address map and no /RESET pin, so swapping them silently changes the system topology. Also note that /03,112 is the tube packaging suffix - if your pick-and-place line needs tape-and-reel, order PCA9541APW/03,118 or PCA9541APW/03,112 with a distributor-kitted reel.
Compliance-Informationen
RoHS-compliant per NXP product page. /03,112 suffix is the tube-packaged commercial grade (not AEC-Q100); choose PCA9541APW/Q900,118 for automotive applications. REACH and halogen-free status were not surfaced in the 2026-10-15 web snapshot and remain flagged unknown until NXP material declaration is consulted.
