Pll Configuration - Texas Instruments DAC348 Series User Manual

Software Control
2.2.1.3 PLL Settings
Follow the steps below to configure the PLL.
1. Enable PLL
2. Uncheck PLL reset and PLL sleep
3. Set M and N ratio such that F
4. For the DAC3482, DAC3484, and DAC34H84: Set the prescaler such that the F
3.3GHz and 4GHz.
5. For the DAC34SH84, Set the prescaler such that the F
6. Set VCO Bias Tune to "1"
7. Charge Pump setting
(a) If stability (P x M) is less than 120, then set to "Single".
(b) If stability (P x M) is greater than 120, then set to "Double" or install external loop filter
8. Adjust the Freq. Tune (coarse tune) accordingly. For additional information, see the relevant DAC348x
data sheet.
6
DAC348x EVM
Figure 3. PLL Configuration
= (M)/(N) x Fref
DAC
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x prescaler is within 2.7GHz and 3.3GHz.
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x prescaler is within
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SLAU432 – February 2012