I need a substitute for the LMH6642 opamp

 

the substitute should be compatible with this circuit

 

What is wrong with the LMH6642? Asking for a substitute for a circuit is too broad of a question. What is the application of the circuit in your design.
Voltage Feedback?
Current Feedback?
High Slew Rate?
Low input bias?

What are your critical parameters?

 

voltage feedback.
I am unable to get the part where i live.
I need something with the same charecteristcs

 

Hi,

What is your application? If we knew something about that, we might be able to suggest alternatives.

 

There are plenty of manufacturers that have parametric searches. Since this is a photodiode application look for the following:

High input impedance
Low input bias current

These two parameters go hand and hand. Low input bias current in the range of pA screams FET input. OPA129 has input bias currents on the order of fA.

 

Would an ADA4851 work?