Datasheet for HMC907 says that pin №21 is RF output for amplifier and connect DC bias (Vdd) network to provide drain current (Idd). Also Drain Bias (Vdd) must be applied through a broadband bias tee or external bias network. And there are only 2 pin that not grounded or not NC.
But scheme for Ev board shows that pins №2, 13, 15, 29, 30 need to be connected to something and 21 pin has no connect to DC source. And there are no descriptions in datasheet about these pins.
So what is right and wrong and what application circuit?
- Application circuit is correct and more straightforward.
- In some case we use the same eval biard for different parts therefore Eval PCb may be misleading.
- you said pin 21 has no connection to DC source, but you need to connect external bias tee,
so Vdd will be applied thru bias tee.
Thank you for answer, Ivan.
I used ATC506WLSM0R47KT815T as choke inductor for Vdd and 530L104KT16T for DC coupling. After that I have gain difference at 1 GHz and 18 GHz in 6 dB. Can this "bias tee" have such affect on frequency response?