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3 votes

Photodiode Signal Temporal Broadening Below Saturation

So to put the question succinctly: Is there a reason, from an electronics perspective, that I should see this premature temporal broadening of the signal as I increase the intensity? Or is it possibly ...
user1850479's user avatar
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3 votes

Photodiode Circuit Output Saturating to 0V. Is there a way to salvage these boards?

You are right. The negative voltage is required. You may be able to lift the pin grounded by mistake. Remove the solder with solder wick. Let it cool. Then use a tiny blade, lift the pin while ...
RussellH's user avatar
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3 votes

Photodiode Circuit Output Saturating to 0V. Is there a way to salvage these boards?

It looks like you've got an inverting op amp configuration as the first stage, but it's centered at 0V. The op amp can never output less than 0V with a negative supply connected to gnd, so the op amp ...
Drew's user avatar
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5 votes

Photodiode Circuit Output Saturating to 0V. Is there a way to salvage these boards?

Suffice it to say all channels are identical? So, concentrating on one: We have an inverting configuration, which takes the photocurrent (drawn from the +5V bias source) into a virtual ground / ...
Tim Williams's user avatar
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0 votes

How to Ground a Photodiode and TIA combination

Since your high voltage supply is providing current to the op amps, AGND and PGND have to be connected. As drawn if AGND is different than PGND then the APD is not reverse biased because the HV ...
user1850479's user avatar
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0 votes
Accepted

TIA with reverse bias adapted

I will just use a TIA without reverse bias. The signal bandwidth is lower due to the larger capacitance, but there is less noise. Since the ADC used has limited speed, the 300kHz bandwidth looks fine. ...
Visje999's user avatar

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