Part Number: LMX2820EVM
Hi,
So I am wanting to verify the locking speed of this particular part when changing from one frequency to another frequency. In my case I am adjusting the output of the synthesizer from 15.5GHz to 16.6GHz. I have the frequency doubler enabled for both the ref 100 MHz and the frequency output, so I have DBLR_CAL_EN. I followed the steps in the evm help menu within in the GUI to configure the synthesizer for Instant calibration and RCAL_EN for VCO Calibration. Once I verified that INSTCAL had been configured I used burst mode to write to register 36 and 43 to adjust the output frequency and performed a write to register 0 to perform a cal. I had an Oscope monitoring the lock detect via the TP_LD testpoint and set to trigger on a falling edge of the lock detect to capture when the synthesizer frequency changed resulting in an unlocked PLL and measured the time for the lock detect to rise with the new frequency. I used SIMPLatinium offered by TI and determined the PLL implemented on the EVM has a lock time of about 30 uS. Currently I'm measuring the lock time to be around 80 uS so there is an additional 50 uS of time that is unaccounted for. I was expecting more around 2 to 3 uS for frequency hopping of the synthesizer. I'm wondering if there is some configuration I need to do to reduce the lock time of the synthesizer.
Burst Mode Commands:
Lock Detect Recovery with frequency hopping:
delta X is 84uS sorry for the bad resolution
