R1

VO

VIN

-

+

R3

VS

RPULL-UP

R2

9

LM397

www.ti.com

SNOS977F – MAY 2001 – REVISED MAY 2016

Product Folder Links: LM397

Submit Documentation Feedback

Copyright © 2001–2016, Texas Instruments Incorporated

8 Application and Implementation

NOTE

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.

8.1 Application Information

LM397 will typically be used to compare a single signal to a reference or two signals against each other.

8.2 Typical Application

Figure 9. Inverting Comparator With Hysteresis

8.2.1 Design Requirements

For this design example, use the parameters listed in Table 1 as the input parameters.

Table 1. Design Parameters

DESIGN

PARAMETER

EXAMPLE VALUE

Input voltage range

0 V to VS – 1.5 V

Supply voltage

5 V to 30 V

Logic supply voltage

(RPULLUP voltage)

5 V to 30 V

Output current

(VLOGIC/RPULLUP)

1 µA to 20 mA

Input overdrive

voltage

100 mV

Reference voltage

5.5 V

8.2.2 Detailed Design Procedure

When using TL331 in a general comparator application, determine the following:

•

Input voltage range

•

Minimum overdrive voltage

•

Output and drive current