Datasheet

LMX2531LQ2820E EVALUATION BOARD OPERATING INSTRUCTIONS
Far-out Phase noise is worse than evaluation board instructions
show
• Ensure the measurement equipment noise floor is not limiting the measurement. For
spectrum analyzers, the noise floor at a particular setting can be measured by removing the
RF input signal
• If the settings are changed from what the board was designed for, ensure the delta-sigma
modulator is not increasing the far-out noise. To determine this, tune to an integer channel
and set the ORDER bit to “Reset Modulator”. The far out phase noise should not decrease. If
it does, try a loop filter with more attenuation or select a lower order delta-sigma modulator.
Device Data
The next few pages show data collected from the LMX2531LQ2820 evaluation board.
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