Member of the Texas Instruments

Widebus Family

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) = 8 pF Typical)

Data and Control Inputs Provide

Undershoot Clamp Diodes

Low Power Consumption

(ICC = 5 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: PCI Interface, Memory

Interleaving, Bus Isolation, Low-Distortion

Signal Gating

description/ordering information

The SN74CBT16212C is a high-speed TTL-compatible FET bus-exchange switch with low ON-state resistance

(ron), allowing for minimal propagation delay. Active Undershoot-Protection Circuitry on the A and B ports of the

SN74CBT16212C 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 SN74CBT16212C operates as a 24-bit bus switch, or as a 12-bit bus-exchange that provides data

exchanging between four signal ports. The select (S0, S1, S2) inputs control the data path of the bus-exchange

switch. When the bus-exchange switch is ON, the A port is connected to the B port, allowing bidirectional data

flow between ports. When the bus-exchange switch is disabled, 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 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, each select input should be tied to GND

through a pulldown resistor; the minimum value of the resistor is determined by the current-sourcing capability

of the driver.