mostly, consumer applications is applied to reduce price and keep performannace.

so I think that application should be applied passive loop filter in consumer market.

at automotive rader application, when active loop filter does not use, what happened?

If have some check point in automotive radar,please advise me?

thank you very much.

An active filter is only needed where the tuning range of the VCO is wider than the tuning voltage of the PLL's charge pump.

For automotive radar it really depends on the VCO being used. In some cases you can get away with tuning over a smaller

range say 1V to 5V to get your required frequency range, in which case the ADF4158 charge pump voltage is sufficient.

Also we are sampling a new device called the ADF4150HV which has a 20V+ tuning range. This would be used with a passive

filter to directly tune wideband VCOs. 

http://www.analog.com/en/rfif-components/timing-ics-clocks/adf4150hv/products/product.html

The scale of the frequency axis in the phase noise plot is in error by a factor of 1000: kHz=>MHz.

Hi Tony,

You're right - the x-axis scale is in kHz rather than Hz so the x-axis title should read
"FREQUENCY OFFSET FROM CARRIER (kHz) "

I have tried this configuration with an ADF4108, however when the power supply is disconnected the information stored in the chip is lost and has to be reprogrammed. It says applications are for automotive and mobile systems which require non-volatile systems, especially in the military. Is there a solution to this problem or have I misunderstood the capability of these synth chips?

Hi rjenkins,

Unfortunately this is a misunderstanding of the device capabilities.  The synthesizer chip don't have non-volatile memory on board, so they will not hold their register values when power is cycled.

Regards,

Brandon