LMV331-N, LMV339-N, LMV393-N

SNOS018G – AUGUST 1999 – REVISED FEBRUARY 2013

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APPLICATION CIRCUITS

BASIC COMPARATOR

A basic comparator circuit is used for converting analog signals to a digital output. The LMV331-N/393-N/339-N

have an open-collector output stage, which requires a pull-up resistor to a positive supply voltage for the output

to switch properly. When the internal output transistor is off, the output voltage will be pulled up to the external

positive voltage.

The output pull-up resistor should be chosen high enough so as to avoid excessive power dissipation yet low

enough to supply enough drive to switch whatever load circuitry is used on the comparator output. On the

LMV331-N/393-N/339-N the pull-up resistor should range between 1k to 10k

Ω.

Figure 12. Basic Comparator

COMPARATOR WITH HYSTERESIS

The basic comparator configuration may oscillate or produce a noisy output if the applied differential input

voltage is near the comparator's offset voltage. This usually happens when the input signal is moving very slowly

across the comparator's switching threshold. This problem can be prevented by the addition of hysteresis or

positive feedback.

INVERTING COMPARATOR WITH HYSTERESIS

The inverting comparator with hysteresis requires a three resistor network that are referenced to the supply

defined as

(1)

(2)

8

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