NXP Semiconductors PCA9548APW,112

Overview

PCA9548APW,112 from NXP Semiconductors is an octal bidirectional I²C-bus switch with active-low reset, enabling selective routing of SCL/SDA signals to one or more of eight downstream SCx/SDx channels. It supports voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V buses, features 6 V-tolerant I/O pins, operates from 2.3 V to 5.5 V, and delivers ≤30 µA operating supply current at 3.6 V - ideal for multi-voltage sensor hub expansion in embedded systems.

For engineers reviewing the PCA9548APW,112 datasheet, PCA9548APW,112 pinout, PCA9548APW,112 application, or PCA9548APW,112 equivalent, this device is selected when system-level I²C bus isolation, hot-insertion support, low-standby-current channel switching, and robust fault recovery via hardware reset are required in space-constrained TSSOP24 layouts.

Technical Context

The PCA9548APW,112 implements eight independent bidirectional pass-gate switches controlled by an 8-bit I²C-accessible register, where each bit enables or disables a corresponding SCx/SDx channel pair. Its internal reset circuitry responds to both power-on (POR) and external active-low RESET assertion, forcing all channels to deselect and clearing the control register.

Voltage translation is achieved through VDD-referenced pass-gate threshold control: Vo(sw) is clamped to ≤2.8 V when VDD ≤ 3.6 V, allowing upstream 5 V masters to safely communicate with downstream 3.3 V or 2.5 V slaves without level-shifter ICs. All I/O pins tolerate up to 6 V regardless of VDD setting.

Key Specifications

Pinout & Package

TSSOP24 package: 24-pin plastic thin shrink small outline package, body width 4.4 mm, lead pitch 0.65 mm, RoHS-compliant, designed for high-density PCB layouts with thermal performance rated at 128 °C/W junction-to-ambient.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C bus switch applications.

Compared with TCA9548APWR and PCA9544APW,112, the PCA9548APW,112 offers the shortest reset pulse requirement (4 ns), highest channel density in TSSOP24, and lowest typical ON resistance - making it optimal for compact, high-reliability, multi-peripheral I²C architectures requiring deterministic fault recovery.

Availability

PCA9548APW,112 is available at Aetrix Electronics and suitable for multi-sensor hub expansion, I²C bus isolation, and multi-voltage system interfacing requiring stable component supply across industrial, automotive, and embedded computing programs.

Supply support for PCA9548APW,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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with leadership in interface, power management, and microcontroller technologies.

The PCA9548A product line was designed to solve I²C bus scalability and voltage-domain interoperability challenges in resource-constrained embedded systems - delivering configurable channel switching, hardware reset, and integrated level translation in a single compact IC.

FAQ

What is the primary function of the PCA9548APW,112 in an I²C system?

The PCA9548APW,112 functions as an octal bidirectional I²C-bus switch that routes a single upstream SCL/SDA pair to up to eight independently selectable downstream SCx/SDx channels. It enables bus segmentation, address conflict resolution, and voltage translation between mixed-voltage peripherals - all under I²C register control. The PCA9548APW,112 achieves this without altering signal timing or requiring external level-shifting components.

How does the PCA9548APW,112 handle voltage translation between different I²C domains?

The PCA9548APW,112 uses its VDD supply voltage to limit the maximum output voltage (Vo(sw)) passed through its pass-gate switches. When VDD is set to 3.3 V, Vo(sw) is clamped to ≤2.8 V, allowing safe communication between a 5 V upstream master and 3.3 V or 2.5 V downstream slaves. External pull-up resistors on each channel set the final bus voltage level. The PCA9548APW,112 itself requires no additional level-shifter ICs or discrete components to achieve this translation.

What is the minimum pulse width required on the RESET pin of the PCA9548APW,112 to guarantee reset activation?

The PCA9548APW,112 requires a minimum LOW pulse width of 4 ns on the RESET pin to reliably trigger internal state machine reset and deselect all channels. This specification is defined in the dynamic characteristics table (tw(rst)L) of the official NXP datasheet. The PCA9548APW,112 also includes a power-on reset (POR) circuit that initializes the control register to zero upon VDD ramp-up, ensuring known default behavior at startup.

Can multiple PCA9548APW,112 devices share the same I²C bus? If so, how is addressing managed?

Yes, up to eight PCA9548APW,112 devices can coexist on the same I²C bus using hardware-configurable slave addresses. Three address pins (A0, A1, A2) allow binary encoding of addresses from 1110000 to 1110111 (0xE0 to 0xE7). Each PCA9548APW,112 must have a unique A0–A2 combination tied to VDD or VSS; no external pull-ups or jumpers beyond these pins are needed. This enables hierarchical bus expansion without address collisions.

What package type and thermal characteristics apply to the PCA9548APW,112?

The PCA9548APW,112 is supplied in the TSSOP24 package (SOT355-1), measuring 4.4 mm body width with 0.65 mm lead pitch. Its thermal resistance is specified as 128 °C/W junction-to-ambient (Rth(j-a)), reflecting moderate power dissipation capability suitable for ambient temperatures from −40 °C to +85 °C. The PCA9548APW,112 requires no heatsink in typical I²C switching applications due to its ultra-low standby current (0.1 µA) and low operating power.