|Description||Hex Schmitt-Trigger Inverters|
|SN7414DRG4 Datasheet PDF : 35 Pages |
SN5414, SN54LS14, SN7414, SN74LS14
SDLS049C – DECEMBER 1983 – REVISED NOVEMBER 2016
9 Application and Implementation
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The SNx414 and SNx4LS14 device is a Schmitt-Trigger input CMOS device that can be used for a multitude of
inverting buffer type functions. The application shown here takes advantage of the Schmitt-Trigger inputs to
produce a delay for a logic input.
9.2 Typical Application
Copyright © 2016, Texas Instruments Incorporated
Figure 28. Simplified Application Schematic
9.2.1 Design Requirements
This device uses CMOS technology. Take care to avoid bus contention because it can drive currents that would
exceed maximum limits. Parallel output drive can create fast edges into light loads, so consider routing and load
conditions to prevent ringing.
9.2.2 Detailed Design Procedure
This circuit is designed around an RC network that produces a slow input to the second inverter. The RC time
constant (τ) is calculated from: τ = RC.
The delay time for this circuit is from tdelay(min) = –ln |1 – VT+(min) / VCC| τ to tdelay(max) = –ln |1 – VT+(max) / VCC| τ. It
must be noted that the delay is consistent for each device, but because the switching threshold is only ensured
between the minimum and maximum value, the output pulse length varies between devices. These values must
be calculated by using the minimum and maximum ensured VT+ values in the Electrical Characteristics.
The resistor value must be chosen such that the maximum current to and from the SNx414/SNx4LS14 is 8 mA at
Submit Documentation Feedback
Copyright © 1983–2016, Texas Instruments Incorporated
Product Folder Links: SN5414 SN54LS14 SN7414 SN74LS14
|Direct download click here|
|Share Link :|