Hello. In a question I sent time ago about ADF4158 and low frequencies, there was an answer with a reference to circuit note CN-0290.
I have built a test board to check it (I almost mimic all the circuitry in figure 2 of the circuit note), but the output signal is not as expected. Instead of having a square signal as in figure 7 of the datasheet, what I have is the same input signal but with less voltage level.
The input signal is a sine wave coming from a VCO and it has not a very high level (less than 0.2 V peak to peak). Wiring the VCO directly to the ADCLK905, the output is a sine wave.
In order to increase the input level, I added a amplifier to have more input level (up to 2.7V) but the output is the same: a sine wave.
What am I doing wrong? Why cannot get the square wave at the outputs?
See attached the schematics of the test board and the input and output signals I get.
Thanks in advance