LMS6002D Quick Starter Manual for Evaluation Board
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P a g e
© Copyright Lime Microsystems
Rev: 2.2
Last modified: 03/05/2012
If all capacitor values are tried and display B is achieved with a mid range value, but the
synthesiser does not subsequently lock then there may be a problem. Please contact Lime
for assistance.
If display A is achieved but at the end of the capacitor range (0 or 63) then the VCO
calibration file will need to be updated.
If the frequency is lowered the cap value goes down, if it is increased the cap value goes up.
Usually the PLL locks over a range of cap values, the optimum phase noise performance is
usually obtained in the middle of the range.
Please note this is a problem solving procedure and these are rules of thumb but not
comprehensive rules. The provided VCO calibration files should set up the synthesiser properly.
If assistance is needed please contact Lime so the root problem with the SPI application software
can be found.
10.2
Is the Correct LNA Selected
If the lower level pages of the SPI SW are used then there are 2 things which need to be changed
to change LNA – the LNA itself on the RX FE page and the output buffer on the RX PLL+ DSM
page.
If the control on the ‘System interface’ page is used both these are changed together and the
correct path will be set up.
10.3
Is the Correct Rx VGA 2 Gain Selected
Default gain for RX VGA2 when the software starts is 3, change it to 30 to get a good level
output for the scope.