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 systems.

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.

• High-Bandwidth Data Path (up to 500 MHz (1))
• Equivalent to IDTQS3VH251 Device
• 5-V Tolerant I/Os With Device Powered Up or Powered Down
• Low and Flat ON-State Resistance (ron) Characteristics Over Operating Range (ron = 4 Typ)
• Rail-to-Rail Switching on Data I/O Ports – 0- to 5-V Switching With 3.3-V VCC – 0- to 3.3-V Switching With 2.5-V VCC
• Bidirectional Data Flow With Near-Zero Propagation Delay
• Low Input/Output Capacitance Minimizes Loading and Signal Distortion (Cio(OFF) = 3.5 pF Typ)
• Fast Switching Frequency (fOE\ or fS = 20 MHz Max)
• Data and Control Inputs Provide Undershoot Clamp Diodes
• Low Power Consumption (ICC = 1 mA Typ)
• VCC Operating Range From 2.3 V to 3.6 V
• Data I/Os Support 0- to 5-V Signaling Levels (0.8 V, 1.2 V, 1.5 V, 1.8 V, 2.5 V, 3.3 V, 5 V)
• Control Inputs Can Be Driven by TTL or 5-V/3.3-V CMOS Outputs
• Ioff Supports Partial-Power-Down Mode Operation
• Latch-Up Performance Exceeds 100 mA Per JESD 78, Class II
• ESD Performance Tested Per JESD 22 – 2000-V Human-Body Model (A114-B, Class II) – 1000-V Charged-Device Model (C101)
• Supports Both Digital and Analog Applications: PCI Interface, Differential Signal Interface, Memory Interleaving, Bus Isolation, Low-Distortion Signal Gating