描述 Description

The SN74CBT3345C is a high-speed TTL-compatible FET bus switch with low ON-state resistance (ron), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the SN74CBT3345C provides protection for undershoot up to ?2 V by sensing an undershoot event and ensuring that the switch remains in the proper OFF state.

The SN74CBT3345C is organized as an 8-bit bus switch with two output-enable (OE, OE\\) inputs. When OE is high or 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 low and OE\\ is high, the bus switch is OFF and the high-impedance state exists between the A and B ports.

This device is fully specified for partial-power-down applications using Ioff. The Ioff feature ensures that damaging current will not backflow through the device when it is powered down.

To ensure the high-impedance state during power up or power down, OE\\ should be tied to VCC through a pullup resistor and OE should be tied to GND through a pulldown resistor; the minimum value of the resistor is determined by the current-sinking/current-sourcing capability of the driver.

特性 Features

? Undershoot Protection for Off-Isolation on A and B Ports Up to –2 V
? Bidirectional Data Flow, With Near-Zero Propagation Delay
? Low ON-State Resistance (ron) Characteristics (ron = 3 Typical)
? Low Input/Output Capacitance Minimizes Loading and Signal Distortion Cio(OFF) = 5.5 pF Typical)
? Data and Control Inputs Provide Undershoot Clamp Diodes
? Low Power Consumption ICC = 3 μA Max)
? VCC Operating Range From 4 V to 5.5 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: USB Interface, Memory Interleaving, Bus Isolation, Low-Distortion Signal Gating