The SN74CB3T3257 is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (ron), 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 VCC. The SN74CB3T3257 supports systems using 5V TTL, 3.3V LVTTL, and 2.5V CMOS switching standards, as well as user-defined switching levels. This device is fully specified for partial-power-down applications using Ioff. The Ioff feature verifies that damaging current does not backflow through the device when the device is powered down. The device has isolation during power off.