Analog Comparator - Freescale
Analog Comparator - Freescale
Analog Comparator - Freescale
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►70Vp-p AC signal from<br />
transformer<br />
►I/O pin for zero crossing detect<br />
►VDD supply = 5V<br />
►Pick single series resistor of R ≥<br />
175k Ω<br />
►Tip – pick order of magnitude<br />
higher R<br />
►Best to have HV isolation<br />
(transformer, ferrites) or limiting<br />
components (diodes, EMI filters)<br />
<strong>Freescale</strong> and the <strong>Freescale</strong> logo are trademarks of <strong>Freescale</strong> Semiconductor, Inc. All other product or service names are<br />
the property of their respective owners. © <strong>Freescale</strong> Semiconductor, Inc. 2007-2008. 47<br />
Current Injection Example<br />
+R ≥ (35V – 5V) / 2mA<br />
+R ≥ 15kΩ<br />
-R ≥ (35V – 0V) / 0.2mA<br />
-R ≥ 175kΩ<br />
TM
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