Non-Inverting Comparator with Hysteresis

A non inverting comparator with hysteresis requires a two

resistor network, and a voltage reference (V

verting input. When V

output to switch from low to high, V

where V

V

When V

comparator switch back to it’s low state, V

before V

V

The hysteresis of this circuit is the difference between V

IN1

and V

Delta V

Circuit Layout and Bypassing

The LMV7235/39 require high speed layout. Follow these

layout guidelines:

1. Use printed circuit board with a good, unbroken low-

inductance ground plane.

2. Place a decoupling capacitor (0.1µF ceramic surface

mount capacitor) as close as possible to V

3. On the inputs and the output, keep lead lengths as short

as possible to avoid unwanted parasitic feedback around the

comparator. Keep inputs away from output.

4. Solder the device directly to the printed circuit board rather

than using a socket.

5. For slow moving input signals, take care to prevent para-

sitic feedback. A small capacitor (1000pF or less) placed

between the inputs can help eliminate oscillations in the

transition region. This capacitor causes some degradation to

t

6. The topside ground plane runs between the output and

inputs.

7. Ground trace from the ground pin runs under the device

up to the bypass capacitor, shielding the inputs from the

outputs.

10135919

FIGURE 1.

10135924

10135920

FIGURE 2. Non-Inverting Comparator with Hysteresis

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