LMV358MM datasheet(28/45 Pages) NSC

28 / 45 page

LMV321-N, LMV321-N-Q1, LMV358-N, LMV358-N-Q1

LMV324-N, LMV324-N-Q1

SNOS012I – AUGUST 2000 – REVISED FEBRUARY 2013

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COMPARATOR WITH HYSTERESIS

The LMV321-N/LMV358-N/LMV324-N can be used as a low power comparator. Figure 72 shows a comparator

with hysteresis. The hysteresis is determined by the ratio of the two resistors.

VTH+ = VREF/(1+R 1/R2)+VOH/(1+R2/R1)

(30)

VTH− = VREF/(1+R 1/R2)+VOL/(1+R2/R1)

(31)

VH = (VOH−VOL)/(1+R 2/R1)

(32)

where

VTH+: Positive Threshold Voltage

VTH−: Negative Threshold Voltage

VOH: Output Voltage at High

VOL: Output Voltage at Low

VH: Hysteresis Voltage

Since LMV321-N/LMV358-N/LMV324-N have rail-to-rail output, the (VOH−VOL) is equal to VS, which is the supply

voltage.

VH = VS/(1+R2/R1)

(33)

The differential voltage at the input of the op amp should not exceed the specified absolute maximum ratings.

For

real

comparators

that

are

much

faster,

recommend

you

use

Texas

Instruments's

LMV331/LMV93/LMV339, which are single, dual and quad general purpose comparators for low voltage

operation.

Figure 72. Comparator with Hysteresis

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Product Folder Links: LMV321-N LMV321-N-Q1 LMV358-N LMV358-N-Q1 LMV324-N LMV324-N-Q1

LMV358MM Datasheet(PDF) 28 Page - National Semiconductor (TI)