Datasheet

LMV7219
www.ti.com SNOS458F –APRIL 2000–REVISED MARCH 2013
Zero-Crossing Detector
The inverting input is connected to ground and the non-inverting input is connected to 100mVp-p signal. As the
signal at the non-inverting input crosses 0V, the comparator's output Changes State.
Figure 19. Zero-Crossing Detector
Threshold Detector
Instead of tying the inverting input to 0V, the inverting input can be tied to a reference voltage. The non-inverting
input is connected to the input. As the input passes the V
REF
threshold, the comparator's output changes state.
Figure 20. Threshold Detector
Crystal Oscillator
A simple crystal oscillator using the LMV7219 is shown below. Resistors R1 and R2 set the bias point at the
comparator's non-inverting input. Resistors R3, R4 and C1 sets the inverting input node at an appropriate DC
average level based on the output. The crystal's path provides resonant positive feedback and stable oscillation
occurs. The output duty cycle for this circuit is roughly 50%, but it is affected by resistor tolerances and to a
lesser extent by the comparator offset.
Figure 21. Crystal Oscillator
Copyright © 2000–2013, Texas Instruments Incorporated Submit Documentation Feedback 11
Product Folder Links: LMV7219