10

LM2903/LM2901

36V Low Power Dual/Quad Differential Comparators

Rev. B

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1

C

4

R

ln2

2

1

Freq









LM393

t

t

Figure 7. Relaxation Oscillator

Windowed Comparator

Figure 8 shows one approach to designing a windowed comparator using a single LM2903/2901 chip. Choose

different thresholds by changing the values of R1, R2, and R3. OutA provides an active-low undervoltage

indication, and OutB gives an active-low overvoltage indication. ANDing the two outputs provides an active-high,

1

)/R

3

R

2

R

1

(R

r

V

OH

V









)

2

R

1

)/(R

3

R

2

R

1

(R

r

V

UH

V











OutA

+InB

+InA

-InB

-InA

LM2903

OutB

UnderVolt

OverVolt

Power

Good

AND

Gate

Figure 8. Windowed Comparator