Control Voltage of the EV-ADF4159EB3Z

Hi Andres, 

The ADF4159 Charge pump output can drive Vtune voltages between 0.5V and 2.8V. 

On the evaluation board, we have placed an active loop filter to drive large Vtune voltages. 

The opamp on the eval board is OP184. According to the OP184 datasheet, this opamp's supply voltage can be as high as 36V. 

So it is possible to use this loop filter to drive the VCO with 25V Vtune input. I recommend supplying the OP184 with 25V, as this opamp is rail-to-rail. 

You need to design and populate the loop filter with suitable values so that you can calculate the values with ADISimPLL. Another important point is the maximum DC voltage values of the C37 and C38. I recommend changing them with suitable capacitors that can withstand 25V DC bias. 

Thanks,
Emrecan

The EV-ADF4159EB3Z also has a loop filter; I saw in some discussions that it does have one and in others that the filter is not included. Which one is correct?

Hi Andres, 

There are two different variants of the eval board. The user guide explains the differences. Here is the screenshot:

Thanks,

Emrecan