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The SN74CBTD3384C is a high-speed TTL-compatible FET bus switch with low ON-state resistance, allowing for minimal propagation delay. This device features an integrated diode to V_CC to provide level shifting for 5-V input down to 3.3-V output levels. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBTD3384C provides protection for undershoot down to –2 V by sensing an undershoot event and ensuring that the switch remains in the proper state.

The SN74CBTD3384C is organized as two 5-bit bus switches with separate output-enable (OE) inputs. It can be used as two 5-bit bus switches or as one 10-bit bus switch. When OE is low, the associated 5-bit bus switch is ON, and port A is connected to port B. When OE is high, the associated 5-bit bus switch is OFF, 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.

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.