2-channel I²C bus multiplexer in 14-TSSOP
The NXP PCA9543APW,118 is a 2-channel I²C multiplexer that lets a single I²C master talk to two independent downstream buses, each with its own address space and pull-up configuration. It is housed in a 14-TSSOP package (4.40 mm width) for surface-mount assembly and is specified for industrial and consumer systems where an I²C bus needs to be split — for example, to isolate devices with conflicting addresses or to drive separate sensor clusters on long traces. This dual-range support means the same part can be used across mixed-voltage designs without a level translator on the multiplexer itself.
Supply voltage — two operating windows
The PCA9543APW,118 operates from either a 2.3 V–3.6 V rail or a 4.5 V–5.5 V rail. If your I²C bus runs at 3.3 V, the lower window covers it; if you are on a 5 V bus, the upper window applies. There is no overlap between the two ranges, so pick the supply that matches your bus voltage — the part will not work at 4.0 V. This is a common gotcha when migrating a 5 V legacy design to 3.3 V: the part itself handles it, but the supply must land cleanly in one of the two bands.