[TriEmbed] I need a circuit that can do this.....

[Chip McClelland]

All, 

OK, before you say it, yes, I first consulted Google before sending this note.  I have not worked with these devices before and the latch operation is the part that I find most confusing. The best device I could find was the MAX9141 <https://datasheets.maximintegrated.com/en/ds/MAX9140-MAX9144.pdf> but the operation of the latch in figure 2 was not what I expected.  

I am looking for a simple circuit which will do the following:
	- Powered, Vcc, by either 3.3V or 5V and should not consume more than 100uA.
	- Connect to the analog output  (ranges from 0 to Vcc) of my Ultrasonic Range Finder <http://www.maxbotix.com/Ultrasonic_Sensors/MB7363.htm> with a high input impedance - potentially with a low-pass filter - we will see.
	- Allow me to set a “trigger threshold” ( 0 to Vcc) using a potentiometer 
	- Compare the input to the trigger and provide a latched digital “high” when the input exceeds the threshold
	- This signal will wake the micro controller using a hardware interrupt and trigger an interrupt routine.
	- The comparator will hold the line “high” input until cleared by the micro controller

Anyone who has a few minutes to take a look please let me know:
	- Is the part I found the right one?
	- Is there a better solution - perhaps using discrete components?


Thank you,

Chip

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