Phase correction in LTC6400 is possbile?

[Paul98]

Hello, I need help if possible. At the output of this circuit I have a phase shift of about 11 ° at 200Mhz. Is there a practical way to reduce it or rather eliminate it? I tried to apply a feedback resistor to the output but without success. At least without losing income. Thanks!.

 

[FvM]

The purpose of showing V(3) magnitude in your post is mysterious.

According to datasheet, the amplifier has an almost constant group delay of about 0.5 ns, the equivalent of 10 cm coax cable length. Constant group delay respectively linear phase is the preferred behavior of an amplifier because if involves no waveform distortion. Noone would try to correct it, technically there's no way to implement a negative delay

 

[Paul98]

I have attached the image showing an out of phase of 11 ° at 200Mhz on one of the unfiltered outputs. I took it for granted because it is based on the standard model scheme. The filter outputs have a greater drift on the phase. Isn't it correct to use it in this way?

 

[mtwieg]

No, you can't really do anything to eliminate that delay (at least not while maintaining a flat magnitude response). But I'm betting you don't need to eliminate the delay. What's your application?

 

[Paul98]

It can be seen as a low signal RF detector but the important thing would be that the output remains in phase without phase shift. And that's why I asked if it was possible to eliminate it. If I use a second stage with an inverting input, can I solve this problem? Thanks.

 

[FvM]

but the important thing would be that the output remains in phase without phase shift

The output remains in phase if you shift the reference plane by 0.5 ns.

 

[Paul98]

How do I do it in a practical way? Delay lane?