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OPA2140: OPA2140 has abnormal output current when used V/I conversion

Part Number: OPA2140


Our customer used OPA2140 as 0~24mA current source, there is no problem during simulation, but actually, he met a question using PCB to test.

1) single 12V  power supply,  0~2V input, and output 0~24mA, there is no problem.

2) When +-12V power supply, there is 0.25~3mA increasement . For example, 1V input, its output is about 10.3mA instead of 10mA. This phenomenon is appeared when 1~2V input. In addition, the output current could only to 18mA and couldn't increase. 

Could you please give some suggestions? Or if is there some pcb layout issue? The circuit is as following:


Best regards