LTC6268-10 1khz bandwith application

Hi Cesur:  If your pulse is 10ns, then you probably want 100MHz bandwidth as a minimum, to capture that pulse.  This is true even if the repetition rate of the pulse is only 1kHz.     

Hi,

Thank you for your answer.  Yes, it is true, I want 100 Mhz bandwidth to capture 10 ns pulse. But repetition is 1khz. Does the noise be too much to work with? The online simulation program offers 24.9 k feedback resistance and a 100 fF feedback capacitor to get 96 Mhz bandwidth. I guess the minimum output of the trans-impedance amplifier will be 10 mV when the laser light comes from 10 meters. Does the noise of the opamp can prevent me to read that signal because the simulator says fast opamp is not proper for low-frequency application.

Thank you.

Hi Cesur:  If you let me know the PD capacitance, then I will be able to calculate the LTC6268 output noise in a bandwidth of 100MHz with 24.9k gain.

Thank you, 2.2 pF at 20V reverse bias.

Regards

Hi cesur and Glen,

I'm thinking you can use LTspice to simulate your circuit.

LTspice shows about 100MHz BW with the conditions you've specified. The RMS noise over the entire bandwidth simulates to around 2.9mV_RMS, as shown below.

Please take a look.

Simulation file:

LTC6268-10 TIA EZ 4_13_20.asc

Regards,

Hooman