Thank you very muchHi,
Obviously capacitive load.
The photodiode includes capacitance, the wiring and last but not least the scope probe.
If you want to improve timing then use a TIA.
Klaus
Did you notice that the datasheet specifies RL = 50 Ω and operation with bias voltage of 5V? Your waveform looks rather like Mohm load and photovoltaic mode (zero bias). Try with a medium load resistor, e.g. 10 kohm if you don't want to go for a TIA.The fall time of this piece was very, very long, about 380 microseconds, while in the information of this piece, the fall time was 67 nanoseconds.
HelloThis part has a TIA inside it.
View attachment 168248
Terminate it with 50 ohms.
View attachment 168249
Regards, Dana.
Hello
What would you suggest to me if I wanted to use amplifiers?
So far I have found that I can use transimpedance amplifiers for my work.
Explain to me if I can follow the parameters that are suitable for my photodiode and the wind in selecting the amplifier.
Hello, I appreciate your help.What's the time constant of a 1Mohm, 7pF probe?
Now loading the diode with 50 ohms may not be
anything like what you want to do for the circuit
task (certainly will reduce photons-to-voltage
output, though current may be unaffected).
The transimpedance amp could improve that
with lower input capacitance, and close-in gain.
You can transform impedance along the way.
Depending on what follows the detector, a (say)
1Kohm load and a 1pF-input-capacitance gain
block might be a suitable compromise. You'd
want to play with that a bit.
OTA converts input voltage difference to current.
Photodiode puts out current in proportion to
illumination, to turn that into a large voltage
wants the transimpedance amp (TIA).
If you had already converted current to voltage
(such as a biased detector and burden resistor)
then the OTA might be suitable.
What circuit are you talking about?you need a low DC load resistance to blead off the stored charge to make the falling edge quicker.
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