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PIR motion sensor - analog output - should I limit output current?

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lee321987

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Hello.
I bought a PIR motion sensor with analog output (Panasonic AMN22112).
Datasheet: https://media.digikey.com/pdf/Data Sheets/Panasonic Electric Works PDFs/AMN Design Manual.pdf
Digi-Key page: https://www.digikey.com/product-detail/en/AMN22112/255-1806-ND/735389

The datasheet says IOut max for analog devices is 50 µA.
Do I have limit this current myself? I plan on connecting the output of the PIR to an ADC input on a PIC microcontroller. The PIC ADC input impedance is 10K. If I connected the PIR output directly to that then 5V / 10K = 500µA which would exceed the 50µA max of the PIR.

Also,
On page 20 there is a wiring diagram (attached pic).
What is RL for? (connected from the sensor's output to ground).
I'm guessing it means "R-Low" and it's a pull-down resistor?
What value should it be? Anything under 100K would exceed the 50µA max.

Please help.
 

The PIC ADC input impedance is 10K.
Click to expand...
No.

What is RL for? (connected from the sensor's output to ground).
Click to expand...
You are showing a connection diagram for a digital sensor. There's no load resistor required for the analog type.
 
FvM said:
You are showing a connection diagram for a digital sensor. There's no load resistor required for the analog type.
Click to expand...
No that is the analog diagram (digital is attached to this post).

Oh, and sorry about my mistake on ADC input impedance (10K is the recommeded _source_ impedance for the ADC). The input impedance on my current chip (PIC 12F1822) is actually about 7K (@5V Vdd).
Still -- that's even lower. Can I damage the PIR by connecting it's output directly to the PIC's ADC input???
 

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  • wiring (digital).png
    wiring (digital).png
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That's what I see in the datasheet

1295856900_1388666883.jpg


The input impedance on my current chip (PIC 12F1822) is actually about 7K (@5V Vdd).
Click to expand...
No, it's the typical sampling switch series resistance which determines the < 1 µs current peak during acquisition. Can be ignored related to sensor output current rating.
 
FvM said:
That's what I see in the datasheet

1295856900_1388666883.jpg



No, it's the typical sampling switch series resistance which determines the < 1 µs current peak during acquisition. Can be ignored related to sensor output current rating.
Click to expand...

Okay:
http://pewa.panasonic.com/assets/pcsd/catalog/napion-catalog.pdf
Has the diagram you posted (no resistor).

But this one (the "Design Manual") has two diagrams with the resistor, on page 20 and 25:
http://media.digikey.com/pdf/Data Sheets/Panasonic Electric Works PDFs/AMN Design Manual.pdf

As far as connecting directly to the ADC... okay, I'll try it (and I'll take full responsibility for whatever happens).
 

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