Hi engineer ：
The scheme is as follows:
Then I test the J11 signal.The J10 is not connect anything.
But the waveform is like this.What are wrong.The input or the power?
Then can I use LT3092 to test the TIA circuit.
Connect J3 to TIA's J10.Looking forward to your reply.Thank you!
To help you with your concern, we would be needing at least these information:
1. Specs of APD or PIN diode2. Mac input current3. Pulse width4. Target Voltage5. Supply Requirement6. Application
Thanks and Regards,
1. Specs of APD or PIN diode
PDF2. Mac input current
3. Pulse width
rise time <5ns
4. Target Voltage
1.5VPP5. Supply Requirement
Because I'm only responsible for the receiving circuit, the transmitter and the APD circuit are not ready yet. How can I test the TIA circuit to verify the design? Thank you very much.
Then I changed C2 to 0.5pF,R2 to 5.11k.J10 connect 0.5pF to ground.It doesn't oscillating. But it have overshoot and noise when there's current flowing through to no current.(I use the LT3092 scheme above to test the TIA circuit) .
Apologies for the late response. I could not respond to your message due to some errors.
Given the specifications, Ipeak=100uA, Vo=1.5Vpp. and APD parameters, LTC6268-10 would be a very good choice. To achieve a 1.5Vpp output, we would need the feedback resistor to 15kohms and a feedback capacitor, Cf>0.14 pF to avoid oscillations. Also, it is worth noting that LTC6268-10 is gain of 10 stable and it is recommended to ensure that the AC gain (Cin/Cf) always 10 or greater.
See image below.
Thank you Jino,
When the transmitter and APD(as above) is ok.I test the TIA circuit.But the TIA output is saturation.Maybe the input current is 20mA.Other conditions are invariant.
Then I use 5mA to simulation use Photodiode Circuit Design Wizard.
Then it is oscillating.The input and the output are all oscillating.The frequency is about 140MHz sinewave. What to do and whether the selection is appropriate.Thank you very much.
You have to adjust the feedback resistor to make sure that the output voltage is below the saturation of the amplifier. Please refer to the image I attached above for sample configuration.
I test my TIA circuit.The scheme of LTC6268 is as follow:
And the waveform is like this.
By adjusting the feedback resistance and feedback capacitance. The oscillation cannot be lowered.Can you help me to eliminate the oscillations?
The LTC6268-10 scheme is as follow.
What about reduce background noise and eliminate overshoot?The background noise is about 160mVPP.The PMT's light current is about 150uA.The rise time is about 10ns.
When I increase the light current to 1mA.In the LTC6268 scheme the oscillation is still very high.Can you help me?Thank you very much.