NXP Semiconductors PCA9547PW,112

Overview

PCA9547PW,112 from NXP Semiconductors is an octal bidirectional I²C-bus multiplexer with active-low reset, enabling one upstream master to selectively route communication to eight downstream I²C channels. It operates from 2.3 V to 5.5 V, supports up to 400 kHz Fast-mode I²C, provides voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V buses, and powers up with Channel 0 enabled-used in server management, modular sensor systems, and multi-peripheral embedded controllers.

For engineers reviewing the PCA9547PW,112 datasheet, PCA9547PW,112 pinout, PCA9547PW,112 application, or PCA9547PW,112 equivalent, key selection criteria include channel isolation integrity, reset recovery timing (tw(rst)L ≥ 4 ns), low Ron (≤ 30 Ω at 3.6 V), 5 V-tolerant I/O, and TSSOP24 thermal performance (Rth(j-a) = 128 °C/W).

Technical Context

The PCA9547PW,112 implements a single-pole, eight-throw analog switch architecture controlled via I²C write to its 8-bit control register, where bits B3–B0 determine channel selection (0000 = Channel 0 default). Its pass-gate design uses VDD as a clamping reference to enable bidirectional level translation without external logic.

It features a dedicated active-low RESET input that forces all channels inactive except Channel 0, resetting the internal state machine and recovering from stuck-bus faults. The device includes no internal pull-ups on address pins A0–A2, requiring external biasing for I²C address configuration (up to 8 devices per bus).

Key Specifications

Pinout & Package

TSSOP24 package (SOT355-1): plastic thin shrink small outline, 24-lead, 4.4 mm body width, exposed pad not present-suitable for space-constrained PCB layouts with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548APWR and PCA9546APW, the PCA9547PW,112 uniquely combines hardware RESET-driven bus recovery, lowest standby current in its class, and full 8-channel capacity in a thermally optimized TSSOP24 package-making it optimal for fault-resilient, power-constrained, high-density I²C systems.

Availability

PCA9547PW,112 is available at Aetrix Electronics and suitable for server baseboard management, industrial PLC I/O expansion, and automotive diagnostic interface applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for PCA9547PW,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 leader focused on secure connectivity solutions for automotive, industrial, and IoT markets, with deep expertise in interface and power management ICs.

The PCA9547 product line delivers scalable I²C bus expansion for systems needing reliable, low-power, multi-peripheral communication-designed specifically for fault-tolerant embedded control and modular system architectures.

FAQ

What is the maximum I²C clock frequency supported by the PCA9547PW,112?

The PCA9547PW,112 supports Fast-mode I²C operation up to 400 kHz, as confirmed in Table 9 of the datasheet. This allows high-speed polling of downstream peripherals while maintaining signal integrity through its low-Ron pass gates and controlled rise/fall times (tr ≤ 300 ns, tf ≤ 300 ns at 400 kHz).

Does the PCA9547PW,112 require external pull-up resistors on its I²C lines?

Yes, the PCA9547PW,112 requires external pull-up resistors on all I²C lines-both upstream (SCL, SDA) and downstream (SCx, SDx)-as stated in Section 1. External pull-ups set the bus voltage level per segment and ensure proper logic thresholds; no internal pull-ups are integrated on any I/O pin.

How does the RESET pin function on the PCA9547PW,112?

The RESET pin on the PCA9547PW,112 is active-low and asynchronously resets the internal state machine. When asserted LOW for ≥4 ns, it deselects all channels except Channel 0, restoring master access. The pin must be pulled up to VDD externally and is not latched-transient glitches may trigger unintended reset if unfiltered.

Can the PCA9547PW,112 translate between 1.8 V and 5 V I²C buses?

Yes, the PCA9547PW,112 enables bidirectional voltage translation between 1.8 V and 5 V I²C buses by setting VDD to the lower of the two voltages (e.g., 1.8 V) and using appropriate pull-ups on each side. Figure 7 and Section 6.5 confirm Vo(mux) clamping behavior, with measured Vo(mux) ≤ 1.5 V at VDD = 2.5 V.

What is the thermal resistance (Rth(j-a)) of the PCA9547PW,112 package?

The PCA9547PW,112 uses the TSSOP24 package (SOT355-1), which has a junction-to-ambient thermal resistance of 128 °C/W, as specified in Table 6. This value assumes standard JEDEC test conditions and guides heatsinking decisions for continuous operation at ambient temperatures up to +85 °C.