General-Purpose, Low-Voltage,

Single/Dual/Quad, Tiny-Pack Comparators

8

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1) Find output voltage when output is high:

2) Find the trip points of the comparator using these

formulas:

which the comparator switches its output from low to

3) The hysteresis band will be:

Ω:

Ω) ≈ 5.0V

Select R2. In this example, we will choose 1k

Ω.

Solve for R1:

0.050V = 5(1000 / (R1 + 1000)) V

where R1

Choose R1 and R2 to be large enough as not to exceed

the amount of current the reference can supply.

current, yet small enough to supply the necessary cur-

Ω and

10k

Ω.

Board Layout and Bypassing

imize performance, minimize stray inductance by

ing trace lengths. For slow-moving input signals (rise

time > 1ms), use a 1nF capacitor between IN+ and IN-

to reduce high-frequency noise.

Chip Information

LMX331/LMX331H TRANSISTOR COUNT: 112

LMX393/LMX393H TRANSISTOR COUNT: 211

LMX339/LMX339H TRANSISTOR COUNT: 411

LMX331

R1

R2

IN+

IN-

OUT

Figure 2. Adding Hysteresis with External Resistors

Package Information

For the latest package outline information and land patterns, go

the package code indicates RoHS status only. Package draw-

ings may show a different suffix character, but the drawing per-

tains to the package regardless of RoHS status.

PACKAGE

TYPE

PACKAGE

CODE

DOCUMENT

NO.

LAND

PATTERN NO.

5 SC70

X5+1

21-0076

90-0188

5 SOT23

U5+2

21-0057

90-0174

8 SOT23

K8F+4

21-0078

90-0176

8 µMAX

U8+1

21-0036

90-0092

14 TSSOP

U16M+1

21-0066

90-0117

14 SOIC

S8+4

21-0041

90-0041