The SN74CB3Q3251 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 SN74CB3Q3251 provides an optimized
interface solution ideally suited for broadband communications, networking, and data-intensive computing
The SN74CB3Q3251 is a 1-of-8 multiplexer/demultiplexer with a single output-enable (OE\) input. The select (S0,
S1, S2) inputs control the data path of the multiplexer/demultiplexer. When OE\ is low, the
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 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 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.