I am looking for a buffer (Analog) with the following requirements:
1) Input voltage range: 0V to 0.9V
2) Fq: ~100MHz to 200MHz
3) Iq, Noise: We don't really care about it
4) VDD: We can provide any VDD between 0.9V to 3.3V (Or may be even higher if needed)
5) Should have very (very) low input capacitance. Kind of main requirement for this buffer. (May be less than 1pF?? I know its difficult to get it) If input doesn't have ESD protection, it will work for us.
6) Input is single ended
I searched the website and found ADA4817-1/2. Is this the closest product for our specs or do you suggest some thing else?
5.5 V is the Abs Max Supply Voltage for LTC6268. This doesn't mean that you have to power the part at 5.5V. The Abs Max Ratings specifies parameters where the part is expected to operate before potential permanent damage. So to answer your concern regarding negative supply, NO you don't need a negative supply as long as your inputs are unipolar since the part can accept inputs down to 0V.
On your first posted questions, you mentioned these requirements:
4) VDD: We can provide any VDD between 0.9V to 3.3V (Or maybe even higher if needed) --- LTC6268 is specified to operate with supply Voltage Range of 3.1 V to 5.25 V. This means that you can power it with Vs=3.3V and the expected performance are defined on pages 5 and 6 of the datasheet.
1) Input voltage range: 0V to 0.9V --- When powered with Vs=3.3V, the amplifier has an Input Voltage Range of 0 to 2.8V. Make sure that your input is within this range to avoid clipping and/or distortion due to IVR limitations.
5) Should have very (very) low input capacitance. Kind of the main requirement for this buffer. (Maybe less than 1pF?? I know its difficult to get it) If the input doesn't have ESD protection, it will work for us. --- Cdiff and Ccm of LTC6268 are 0.1 pF and 0.45 pF respectively.