What this bus switch does on your board
The SN74CB3Q3345RGYR is an 8-bit, 1:1 bus switch from the 74CB family, designed for isolating or connecting digital signals on a PCB without adding propagation delay. It operates from a single 2.3V to 3.6V supply, making it a direct fit for 2.5V and 3.3V logic rails in mixed-voltage systems. Each of the eight channels passes a digital signal with minimal on-resistance, preserving signal integrity in high-speed buses like SPI, I²C, or GPIO expansion. The switch is bidirectional, so data flows in either direction when the output-enable pin is asserted.
Running at 2.5V reduces dynamic power; at 3.3V the switch delivers its lowest on-resistance. The single-supply architecture simplifies the power tree — no separate VCC for the switch core and the I/O buffers.
The 20-VFQFN package with exposed pad (3.5 mm x 4.5 mm body) requires a thermal land pattern on the PCB for both heat sinking and mechanical stability. Surface-mount assembly on a standard reflow profile (lead-free, 260°C peak) is fine.
ROHS3 compliance is confirmed, so no exemption expiry concerns for EU or California markets. The 74CB series is a mature logic family; production is stable. Confirm the date-code and lot traceability requirements at quote time — we can provide manufacturer trace documentation for audit trails.