The SN74CB3T3257 is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (r_on), allowing for minimal propagation delay. The device fully supports mixed-mode signal operation on all data I/O ports by providing voltage translation that tracks V_CC. The SN74CB3T3257 supports systems using 5-V TTL, 3.3-V LVTTL, and 2.5-V CMOS switching standards, as well as user-defined switching levels (see Figure 1).

The SN74CB3T3257 is a 4-bit 1-of-2 multiplexer/demultiplexer with a single output-enable (OE)\ input. The select (S) input controls the data path of the multiplexer/demultiplexer. When OE\ is low, the multiplexer/demultiplexer is enabled, and the A port is connected to the B port, allowing bidirectional data flow between ports.