FEATURES

· 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 (r on)

Characteristics Over Operating Range

(ron = 4 W Typ)

· Rail-to-Rail Switching on Data I/O Ports

– 0- to 5-V Switching With 3.3-V V CC

– 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)

(1) For additional information regarding the performance

characteristics of the CB3Q family, refer to the TI application

report, CBT-C, CB3T, and CB3Q Signal-Switch Families,

literature number SCDA008.

· 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

DESCRIPTION/ORDERING INFORMATION

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.