RF_IN_A and RF_IN_B of ADF4110 are differential inputs with 500ohm resistance fixed at 1.6V. Figure 29.
Table 4. Pin Function Descriptions are shown as follows.
RFINA Input to the RF Prescaler. This small-signal input is ac-coupled from the VCO.
and, RFINB should be decoupled to the ground plane with a small bypass capacitor.
This is Single-Ended drive.My question is that point.
My circuit consists of a PLL with ADF4110 and VCO as nearly shown in Fig. 33.
My VCO has a differential LVDS output. Not a Single-Ended output.
I thought it would be advantageous from the signal integrity point of view to terminate between RF_IN_A and RF_IN_B with a adjustment load resistance of less than 320 mVp-p.
Isn't it desirable to connect directly with a differential DC coupling?
Please tell me some advice.