Hi, I am looking for an analog phase shifter on 3GHz, and I see ADI has two analog phase shifter IC HMC247 and 877. But the listed lower frequency limit is 5GHz for one and 8GHz for the other. My question is if I could use the devices on 3GHz at all ? I don't care if the phase shift range gets reduced at 3GHz, as long as the rf gets through without too much loss, and the phase control still has some effect. Thanks - H.
Regarding the HMC247, we have S-parameter data only as low as 4 GHz, so I don't have the data with which to answer your question regarding 3 GHz operation. Regarding the HMC877, I'll need to look at the data set we have and review its data sheet to better understand its operation before I can comment.
Do you care about absolute phase shift or do you just need to be able to modulate the phase such that you achieve a certain relative phase change? If you just need to modulate the phase then I wonder if the HMC631LP3E Vector Modulator 1.8-2.7 GHz (a packaged part, not a die) would do what you need. It allows analog control of both gain and phase, so you would need to apply I and Q analog control signals of the proper values for holding the gain constant while shifting the phase by the desired amount. The part would give you gain in positive dB, rather loss like the HMC247. For the HMC631 we have 1.0-3.0 GHz S-parameter data (in .mdif format) from which the 3.0 GHz performance could be seen.
Let me know if your preference is for die or packaged part and if using a vector modulator to achieve a relative phase shift is an acceptable option.
Hi SMcBride, thanks for your reply and sorry for my late response as I just received the newsletter and saw your reply. My application for the phase shifter is to compensate the phase drift in a 3GHz rf reference distribution line detected by a phase comparator. The required phase control range is less than 10 degrees on the 3GHz scale. No I don't care about the absolute phase drift on the phase shifter, as that would be detected by the phase detector and gets corrected by the phase loop. I am aware of the gain change issue with those analog phase shifter. I am hoping the change would not be too significant if the phase control range is limited to only a few degrees. I am quite familiar with the Vector modulators as well. I am trying not to use a vector modulator for this application to avoid the need for processor support (to get the required I/Q control data). I want the phase loop to be a dumb analog circuit, thus to be able to operate on its own , no need for computer, network, reboot/reset etc. So my question is whether the ADI analog phase shfiter could let a 3GHz to pass (without too much loss), and still give me a phase control of few degrees. Thanks.
Good news! For the HMC247 I was able to locate some S-Parameter vs. Vctl data as low as 0.05 GHz.
I've processed the +25C data into a flat file that can be easily imported into Excel or other application capable of reading .txt files.
This data set will show you how much of a 3.0 GHz phase shift can be obtained through variation of the Vctl voltage from 0V through 10V.
Let me know if you need additional help interpreting the data.
Thank you very much for the data in which I have found the answer.
with best regards,