The SN74CB3T16211 is a high-speed TTL-compatible FET bus switch 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 SN74CB3T16211 supports systems using 5-V TTL, 3.3-V LVTTL, and 2.5-V CMOS switching standards, as well as user-defined switching levels.
●The I/O port of this device has a pullup current source that maintains the output voltage at VCC when the device is ON, and the input is greater than or equal to VCC – 1. Because of the pullup current source, the output voltage level may be less than VCC when the operating frequency is low and the I/O port is connected to a pulldown resistor. In order to maintain the output voltage at VCC, a pullup resistor must be connected to VCC instead of a pulldown resistor to ground.
●The SN74CB3T16211 is organized as two 12-bit bus switches with separate output-enable (1OE, 2OE) inputs. It can be used as two 12-bit bus switches or as one 24-bit bus switch. When OE is low, the associated 12-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 12-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 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.
