unable to achieve gain using AD8003

before entering in to problem:

my application is a laser pulse detection, in this process when a laser pulse falls on photo diode it generates current, later stages include a I-V conversion, Gain,difference amplifier and comparator

my pulse characteristics:

pulse width min:10ns max:150ns rise/fall time:2ns-5ns pulse to pulse width:22uS

How i selected the opamp for Gain and difference amplifier stages

key parameters: BW - bandwidth and SR - Slew Rate

from this literature i found my BW can be calculated by formula

BW=0.35/(rise time)=0.35/5ns=70MHz

Now slew rate is to be calculated

SR = 2 * 3.14* BW * Vp = 2 * 3.14* 175MHz *4V = 2198V/us

So Matching both these parameters is a CFA AD8003 from Analog, when i go for high slew rates and high BW almost all opamps avaliable are CFA's !

here below is the desing as suggested in datasheet, pulse here is a 10ns pulse with 100ns repetetion and 1V amplitude fromt the voltage source, i used the TIs TINA simulation and imported the spice model given by Analog Devices

results are quite unexpected

Attachment is the design of the above circuit which can be opened and simulated using TINA, because i did not find AD8003 in analog simulator and i was not able to import the spice model to ADI simulator

Kindly help in taking the advantage of AD8003

GAIN_AD8003.TSC.zip
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    •  Analog Employees 
    on Aug 2, 2018 3:27 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin
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  • 0
    •  Analog Employees 
    on Aug 2, 2018 3:27 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

    Thank you,
    EZ Admin
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