thank you for your answer，
But I've added the REF pin a voltage（2.5V） by op184，Is this not a right way？
how should I set？
My answers to your questions are as follows:
Q: With this contraints I want to use a neg. Buck Converter to supply -5V to the OP184 and to AVss, to be with the output linear down to 0V at Codeword “0x0000”. May I am correct with my thought…
here is the schematic. The inputs arrive from 9GHz IQ mixer HMC908 via 2x10uF capacitors.
Maybe c27 has to be increased.
P5VRF and P5VDIG derive, after filtering, from a 7805. there are no switching regulators on the board.
The outputs feed…
ADI has so many available op amps in DIP but OP284/OP484 best suits all your requirements. OP184 can operate from 3V to 36V, is unity-gain stable, has rail-to-rail input and output, has an output current of +/-10mA and can operate in the industrial…
Unfortunately, my evm does not work at all with my external VCO. I tested the VCO alone and it work good. I rebuilt a loop filter according to ADsimPLL for the correct ADF chip, my VCO parameters, OP184 opamp at 5V etc....All supply voltage seem ok. It…
I understand that you have external to the evaluation board , an active loop filter and VCO, for this configuration to work, you should isolate and power down the on board active loop filter and VCO, while at the same time connect your…
"OPA" is a T.I./Burr-Brown prefix; did you mean OP184?
The next generation part is out, the ADA4084-1, so let's use that one.
You didn't say which you wanted, but the differential input impedance and common mode input
Thanks for your clarification. Since you recommended a low GBP op-amp for Cext to track RFIN, does it mean we only care about tracking at low frequency? For the Op-amp, I am choosing OP184. It has 4MHz GBP but pretty low noise performance…