Hi,
I'm current working on a photodiode circuit. My schematic for the circuit is below:
http://img829.imageshack.us/img829/33/transimpedanceamplifier.png
Below are the datasheets for the op-amp and photodiode used:
http://www.ti.com/lit/ds/symlink/lmv793.pdf
http://pdf1.alldatasheet.com/datasheet-pdf/view/45619/SIEMENS/SFH206K.html
The issue i have at the moment is the output reading doesn't seem to be what i'd expect. I've tried using different resistor values, and when i decrease the resistor value, the output voltage reading increases, which shouldn't be the case given that for this transimpedance layout, Vout/Iin = -Rf.
Also, when i place my laser diode (655nm wavelength) onto the sensitive area of the photodiode, the output voltage doesn't change.
Here are some photos of the circuit:
http://img812.imageshack.us/img812/9346/img0417ylf.jpg
http://img841.imageshack.us/img841/1977/img0414wk.jpg
Please note, i rotated the op-amp the other way round for convenience in the circuit layout. Also, the reason i'm using a surface mount component like this is because the other components are through hole.
Any help would be appreciated.
Thanks.
I'm current working on a photodiode circuit. My schematic for the circuit is below:
http://img829.imageshack.us/img829/33/transimpedanceamplifier.png
Below are the datasheets for the op-amp and photodiode used:
http://www.ti.com/lit/ds/symlink/lmv793.pdf
http://pdf1.alldatasheet.com/datasheet-pdf/view/45619/SIEMENS/SFH206K.html
The issue i have at the moment is the output reading doesn't seem to be what i'd expect. I've tried using different resistor values, and when i decrease the resistor value, the output voltage reading increases, which shouldn't be the case given that for this transimpedance layout, Vout/Iin = -Rf.
Also, when i place my laser diode (655nm wavelength) onto the sensitive area of the photodiode, the output voltage doesn't change.
Here are some photos of the circuit:
http://img812.imageshack.us/img812/9346/img0417ylf.jpg
http://img841.imageshack.us/img841/1977/img0414wk.jpg
Please note, i rotated the op-amp the other way round for convenience in the circuit layout. Also, the reason i'm using a surface mount component like this is because the other components are through hole.
Any help would be appreciated.
Thanks.