Non linearety ADL5565


In my circuit i have an ADL5565 powerd by +/- 2.5Volt( see picture below) DC coupled .

When i apply a differential ramp voltage to the input( Pin 2: -0.5V...0.5V and Pin 3: 0.5V...-0.5V) i see a huge nonlinearety of +/- 75ppm.

I becomes smaller with a smaller input voltage:

Input           Output          Error

2Vpp_diff     4Vpp_diff     +/-75PPM

1Vpp_diff     2Vpp_diff     +/-30PPM

0.5Vpp_diff  1Vpp_diff     +/-11PPM  

The shape of the non-linearety look like the picture below

An DC offset on the input does not influence the linearety.

Is this a know issue with the ADL5565 and is this frequency dependent?

In de datasheet there is not a lot of information about DC-couppled circuits.

I hope someone can tel me more about this issue

Thanks in advance foor any reaction