I am designing the front end(single ended to differential) for the ADC using LTC6406 to interface with the 20MSPS ADC. My input frequency is 140 MHz. Simulation Sch is shown below:

L1, L2 and C1 are used to make the filter of 140MHz. When I fed input of 140MHz 2Vpp with DC offset of zero, it works fine. Waveform shown below:

But when I fed this circuit with 140MHz, 2Vpp with DC offset of 1V, I get the waveform shown below:

Can the output waveforms shown in both the figures be fed to ADC and ADC will give same response.

I am unable to make out the modification in circuit for 140MHz, 2Vpp, 1V DC offset. And looking into part numbers of L1, L2 for 140MHz filter, the datasheet of the inductor talks about self resonant frequency and Q factor of inductor. How Q and resonant frequency of inductor will affect my filter.

Final Edit: Here is the rectified Sch with waveform:

• If you look at V(out+) - V(out-), does it look like V(in)? – The Photon Aug 27 '13 at 18:00