8.1 Overview

The SN74CB3T3215 device is organized as four 1-bit bus switches with separate ouput-enable (1OE, 2OE, 3OE, and 4 OE) inputs. When OE is low, the associated 1-bit bus switch is ON, and the A port is connected to the B port, allowing bidirectional data flow between ports. When OE is high, the associated 1-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 Ioff. The Ioff feature ensures that damaging current will not backflow through the device when it is powered down. The SN74CB3T3125 device has isolation during power off. To ensure the high-impedance state during power up or power down, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.