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OPT101 - Ti - Vibration problem - HELP!

D

Design Group

Jan 1, 1970
0
We designed a device that detects very low light levels
(micromillilamberts) and used the OPT101. In testing, the OPT101
produces an output pulse up to .3-.8V when lightly tapped with a
plastic rod. It resets shortly after but these problems cause our
device to malfunction.

Has anyone used an OPT101 with a 10-30M feedback resistor successfully
in environments with some vibration?
 
J

John Popelish

Jan 1, 1970
0
Design said:
We designed a device that detects very low light levels
(micromillilamberts) and used the OPT101. In testing, the OPT101
produces an output pulse up to .3-.8V when lightly tapped with a
plastic rod. It resets shortly after but these problems cause our
device to malfunction.

Has anyone used an OPT101 with a 10-30M feedback resistor successfully
in environments with some vibration?

The high current to voltage gain of this circuit makes it very
sensitive to any sources of changing current, including any moving
charges. Are you sure it is not the moving static on the plastic rod
you are amplifying, not the vibration of the circuit? Any parts with
voltage on them have electric fields around them, and any movement of
those parts near the input node will generate capacitive currents to
that node. Good electrostatic shielding over the detector die is
important. Shielding between the supply and output nodes of the
amplifier and the input node is also important. Otherwise these DC
potentials are a source of AC if they move with respect to the input
node.
 
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