h1_key

The SN74CBT3253C is a high-speed TTL-compatible FET multiplexer/demultiplexer with low ON-state resistance (r_on), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBT3253C provides protection for undershoot up to -2 V by sensing an undershoot event and ensuring that the switch remains in the proper OFF state.

The SN74CBT3253C is organized as two 1-of-4 multiplexer/demultiplexers with separate output-enable (1OE, 2OE) inputs. The select (S0, S1) inputs control the data path of each multiplexer/demultiplexer. When OE is low, the associated multiplexer/demultiplexer is enabled, and the A port is connected to the B port, allowing bidirectional data flow between ports. When OE is high, the associated multiplexer/demultiplexer is disabled, and a high-impedance state exists between the A and B ports.

This device is fully specified for partial-power-down applications using I_off. The I_off feature ensures that damaging current will not backflow through the device when it is powered down. The device has isolation during power off.

To ensure the high-impedance state during power up or power down, OE should be tied to V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.