My photo diode is here Characteristics are PW 10ns-150ns, PRF - 1Hz-1Khz, current output 10nA-100mA
i have selected a TIA for processing the above signal to an extent, by using LT spice simulator i was able to simulate the IC and its behavior and checked the performance to an extent.
but i want to emulate the photo diode behavior so that i can feed a signal similar to photo diode to my read out circuit
in short i want to know how can i create a current source, in fact a pulsating current source with above characteristics,
What i want to try :
to solve the problem i have decided to go with a voltage source like this, what if i place a series resistor between TIA input and voltage source, by tweaking the series resistor wont i be able to change the current to the TIA ? am in the right direction ?? is there any alternate approach to create a current source having above characteristics ?
Any way due to opamp saturation at maximum the current can only go to vcc/rf which is 2.5V / 1K= 2.5mA
Please observe that the circuit shown is meant only to showcase what am i trying.
I want to generate a minimum current of 30uA and maximum 2.5mA with above pulse characteristics, The voltage source is a positive polarity one, while i have negative polarity supply also, link to source
As raised by the answers, to clear more on the circuit, the circuit involves a protection diode at opamp input to surge extra current and also protect opamp input from voltage greater than 2V, the TIA is followed by a inverter then a high speed comparator which is a LVDS output having a 100 Ohm termination, that is it !
Something like this :
I know few short comings of the circuit, i want measure as much is possible from the circuit,please throw your comments more on creating current source of characteristics discussed in background, if not the above circuit i can experiment with some other, but my main intention in this question is to discuss and come to a conclusion on the best way to create a valid current source