OPA320 split supply problem

Hi there,

I am having problem in split supply of OPA320. I am using LM336 reference diode for the supply of 2.5v and -2.5v.

Problem is when I connect LM336 output to V+ of OPA320 it is giving only 0.6v and varying with resistor values. At 470ohms it becomes 2.49v. Same for negative supply voltage (V-). It should rather be stable for different resistor values depending on the Iz.

And when I disconnect it from op amp it gives correct and stable output(from resistor 470ohms -10k), I don't know why this is happening.

For negative supply i have used 555 astable and charge pump circuit and LM336 reference diode. Also using supply voltage of 5v and converting it 2.5v from LM336.