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Typical Measurement
7
SNAU217A – August 2017 – Revised November 2017
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LMX2572EVM Evaluation Instructions
Table 2. Phase Adjustment Setting
PARAMETER
EXAMPLE VALUE
MASH_SEED
800
PLL_DEN
1000
CHDIV
32
VCO_PHASE_SYNC_EN
0
Phase shift = 360° × (800 / 1000) × (1 / 32) = 9°. We can write 800 to MASH_SEED 40 times to get 360°
phase shift.
Figure 7. Phase Adjustment Setting
Figure 8. Phase Adjustment
3.2.2
Calibration-free Automatic Ramping
LMX2572 supports linear frequency ramp without the need of VCO calibration in the middle of the ramp.
The output waveform is a continuous frequency sweep between the start and the end frequencies.
However, the frequency ramp range is limited. When using ramp, the followings need to be set
accordingly:
•
OUT_FORCE = 1
•
LD_DLY = 0
•
PLL_DEN = 2
32
– 1
