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PLL NOT WORKING IN TEMPERATURE

Sir,

Pls help to find an unlocking issue in PLL ckt using AD4156 and HMC587 VCO.It became unlock b/w the temperature range of +17 to +20 C.Freq is 5.5GHZ.It is working fine above and below this range.

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  • Sir,

    Finally I could find out the problem.The pad of LNA detached (very very small portion) from the body.The image attached is taken using a magnifier having 110 zoom.HMC 587 output is divided using…

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  • Can you isolate the problem to see if it is the ADF4156 or the HMC587 that is failing?

    • Is there any output from the VCO at these temperatures? Are all the supply pins at the correct voltage?
    • For the PLL, can you program the various Muxout modes? i.e. when the loop is failing, can you program DVDD and GND on Muxout and measure them with a multimeter?
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  • Can you isolate the problem to see if it is the ADF4156 or the HMC587 that is failing?

    • Is there any output from the VCO at these temperatures? Are all the supply pins at the correct voltage?
    • For the PLL, can you program the various Muxout modes? i.e. when the loop is failing, can you program DVDD and GND on Muxout and measure them with a multimeter?
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