描述 Description

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.

特性 Features

? High-Bandwidth Data Path (Up to 500 MHz)
? Equivalent to IDTQS3VH384 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 Typical)
? 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 Typical)
? Fast Switching Frequency (fOE\\ = 20 MHz Max)
? Data and Control Inputs Provide Undershoot Clamp Diodes
? Low Power Consumption (ICC = 1 mA Typical)
? 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
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.