What this part is and where it fits
The NXP PCA9543AD,118 is a 2-channel I²C multiplexer designed to route I²C or SMBus traffic between a single upstream bus and two downstream channels. It lives in a 14-SOIC package (0.154" body width, 3.90 mm) and operates from a 2.3 V to 5.5 V supply, which means it drops into both 3.3 V and 5 V logic systems without a level translator.
Supply voltage and logic compatibility
The 2.3 V to 5.5 V supply range covers the two most common I²C bus voltages. If you're running a 3.3 V bus, the PCA9543AD works without extra pull-up adjustments. At 5 V, it handles legacy 5 V-only peripherals. The I²C and SMBus interface support means it can be used with standard I²C controllers or SMBus hosts — just check the bus capacitance and pull-up resistor sizing for your channel count.
Package and mounting
The 14-SOIC package is a surface-mount footprint that's easy to hand-solder or reflow. The 0.154" body width is the narrow SOIC variant, so verify your PCB land pattern matches the 3.90 mm width. Available in Tape & Reel (TR) or Cut Tape (CT) options — the Tape & Reel is the standard for automated pick-and-place, while Cut Tape suits prototype or small-batch builds.
Lifecycle and sourcing
The PCA9543AD,118 carries an active lifecycle status — no end-of-life notice, no last-time-buy window. It's ROHS3 compliant. For production quantities, the Tape & Reel option is the usual choice; for evaluation or repair, Cut Tape works.