There is some information about single-ended input impedance, shown in the table 1. It seems the data were measured on the demo board. Can you provide deembedded S-parameters of the LTC5582 up to 10 GHz?
I simulated the S11 file available from ADI's website and return loss was about 7dB and expected return loss should be 10dB. What reference plane was used to measure S11?
Do you have the de-embedded S11 measured at IC pins (Differential IN+ and IN-) so that I can design the matching network?
the s11 file measured on the eval board with reference plane at the end of the transmission line.
we don't have s-parameter that de-embed the pcb.
use a shunt 68ohm resistor at the input for simulation, that is the recommended matching.
Thank you for replying. If the S11 (available from ADI's website for LTC5582) is measured on the Eval board (J1 RFIN connector on Demo circuit 1528A), why is the return loss as 7dB. The 68 ohm shunt resistor should help to maintain 10dB return loss as described in datasheet.
Here are the results. The red curve is S11 file (from ADI's website) and blue curve is the measurement I did on the Demo board 1528A at RFIN connector. The return loss loss is 8.2dB at 1.6GHz which is not meeting the 10dB spec as described in datasheet. I need the S11 measured at the pin of LTC5582 so that I can design an optimum matching network with 68 shunt resistor and decoupling capacitors. Thank you.
Another question. If the S11 (available from ADI's website for LTC5582) is measured on the Eval board (J1 RFIN connector on Demo circuit 1528A), why are the results not correlating to the results I have measured on the demo board. I also measured at J1 connector.
please see attached S11 measured on the DC1528A eval board.
the matching includes the coupling capacitor and the shunt resistor, used in the standard demo board.
The return loss is better than 15dB at 1.6GHz.The return loss is better than 15dB at 1.6GHz.