Could you please suggest an ADI device to provide the PLL reference signal for the ADRF6820 demodulator and ADRF6720 modulator?
The required reference frequency is up to 320MHz and amplitude is +4dBm typical, operate upto +14dBm. Performance data on datasheet is with CW signal on signal generator(R&S SMT06 or equivalent, refer to Figure 57 of ADRF6720 datasheet).
Reference requirement of ADRF6720 & ADRF6820 is similar to one for PLL. We are using TCXO(vectron, Rakon) as an reference source on PLL evaluation board. We don't have those kind of crystal oscillator.
I put Rakon TCXO( was the Rakon 509540 38.4MHz IT2205AE TCXO. However, changed the part number to Rakon newer TCXO platform, 38.4MHz IT2205K TCXO (511942)) ON ADRF6720 Evaluation board. Please refer below link for the comment about this and schematic as reference on the user guide.
And PLL evaluation boards use also either Vectron(122.8MHz, VCC6-LAB-122-LAB122M880000) or Rakon TCXO(TXO225B). Refer the schematic on below user guides.
Thanks a lot for our answer.
I was wondering if I could use just one TCXO and a buffer. Can a simple op-amp be good for?
Is there any particular reason for using a sine wave rather than a square one?
Is the ADRF6820/6720 PLL much different from ADF4351? Or at least the REFIN section.
I believe the amplitude of TCXO is enough to drive the reference of ADRF6720/6820 as well as ADF4351. So I don't think you need an additional buffer amplifier. If you look at the evaluation board schematic of ADRF6720 and ADF4351, basically it is same. Please refer to the reference circuit on those evaluation board schematic. As a reference signal source for ADRF6720/6820, both a sine wave and a square wave are okay. We used a sine wave from a signal generator in product characterization because we need to characterize and do product evaluation at several difference reference frequencies that TCXO doesn't support. Because of this reason, characterization board doesn't have a option to get a reference clock from TCXO.