IRS-B210ST01 PIR sensor

[savage67]

Hi everyone
I am aiming to design a PIR sensor application with IRS-B210ST01 PIR sensor from Murata company but there is not enough information about the output voltage characteristic of sensor. Just:
Responsivity (500K, 1Hz, 1Hz) = 3.6mVp-p(Typ)

I wonder that any offset voltage or any negative voltage could seen at output pin.(Actually offset voltage is not possible)

What is the means of 3.6mVp-p?

Regards.

 

[hakeen]

Hi Savage67,

it was some time ago, have learnt some about these sensors. I hope I remember correctly.

firstly 500K,1Hz,1Hz means an object with color temp of 500K, at 1 Hz center-frequency with 1Hz Bandwith (bandpass).
This range is optimum for humans and most of (domestic) animals.

3.6mV is the typical peak voltage. So imagine an bandpass filter-like graph, where 3.6mV peak at nearly 1Hz.
It is normal MURATA is not defining any offset or rms or similar voltage (which is surely there, even if in uV/nV - due to basic thermodynamics rules), because it should be probably difficult to test and guarantee because of serial production and other tolerances.

If you notice 3,6mV is also defined as typical (not "max"). The peak is important for next stage, that is often an emitter-follower.
Range of Freq<1Hz or >1Hz has a 20dB/decade for (typically for LiTaO3-based Sensors) voltages.

Pity Murata technical document is quite "thin". Check PerkinElmer's website for more detailed info in app notes.


I hope this helps.