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 Ω 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

description/ordering information
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. 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, 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.