Datasheet

7–133
Detailed Comparison
The major subject areas covered in this application report are:
• Input characteristics
• Maximum input slew rate
• Output characteristics (drive capability)
• 5-V tolerant inputs/outputs
• Power consideration
• Package power dissipation
• Output capacitance
• ac characteristics
• Advanced packaging
• Bus hold
• Partial power down and live-insertion capability
• Power-up and power-down high impedance
• Additional design considerations for GTL and BTL/FB
The characterization information provided is typical data and is not intended to be used as minimum or maximum
specifications, unless noted as such. All devices used in this application report are of the Widebus families, except for LV,
which uses octal devices instead (Widebus packages are not available).
For more information on TI logic products, please contact your local TI field sales office or an authorized distributor, or call
Texas Instruments at 1-800-336-5236.
This application report provides engineers with the information necessary for a better understanding of TI advanced logic
products. These products vary from low speed; low drive to high speed; and high drive with multiple power grades, depending
on the technology, as well as the power supply. This report discusses in more detail the characteristics of these
families, including:
• I/O structure and impedance
• Maximum input slew rate that is tolerated before the device begins to oscillate
• Ability of I/Os to retain data when powered down (selected families only)
• Ability of output to remain in high-impedance state when V
CC
is ramping up or down
• Ability of 3.3-V inputs and outputs to withstand and drive 5-V signals
• Live-insertion capability (selected families)
• ac characteristics, such as power consumption, noise immunity, capacitive loading, speed, ground bounce, rise and
fall time, skew, and packaging
Each family performs uniquely, depending on the design application. Understanding these characteristics will help designers
choose the right family for the best design. This comparison reveals that TI provides a compelling solution in both
point-to-point and backplane environments.
Several devices from each family were used to study the various performance levels. Characterization boards with standard
loads (as specified in data sheets) were used in most cases to perform the laboratory work supporting this application report.
A 10-MHz input frequency was used, unless otherwise noted. A resistive termination to both V
CC
and GND was used, except
for FB and GTL, which require a resistive load to V
CC
only. Figure 1 illustrates all switching standards that are used in this
application report.