8-Bit 2.5-V/3.3-V Low-Voltage FET Bus Switch

The SN74CB3Q3245 is a high-bandwidth FET bus Switch utilizing a Charge Pump to elevate the Gate voltage of the pass Transistor providing a low and flat ON-state resistance (ron). The low and flat ON-state resistance allows for minimal propagation delay and supports Rail-to-Rail switching on the data input/output (I/O) ports. The device also features low data I/O capacitance to minimize capacitive loading and signal distortion on the data bus. Specifically designed to support high-bandwidth applications, the SN74CB3Q3245 provides an optimized Interface solution ideally suited for Broadband Communications networking, and data-intensive computing systems. The SN74CB3Q3245 is organized as an 8-bit bus Switch with a single output-enable (OE) input. When OE is low, the 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 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 circuitry prevents damaging current 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.
By Texas Instruments