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DAC38RF93: on chip PLL, KVCO parameter

peleg bs
Prodigy 20 points

Part Number: DAC38RF93

hello all,

In our design we use with high speed DAC38RF93.

In one of our application we need to work with sampling rate of 7920MHz (using the internal PLL).

The internal PLL have two VCO's with ranges: 1: VCO0 - 5240MHz to 6720MHz, 2: VCO1 – 7960MHz to 9000MHz.

Because we work outside the range of VCO1 we want to know what the KVCO of VCO1 (Fout VS Vtune graph) for stability analysis.

I want to mention that I tried this configuration at room temperature and it work ok, but we need to proof that the system is stable in this mode.

Can I get this parameter? And maybe someone can add some extra data about the stability of the PLL/VCO in this frequency.

thanks ahead,

Peleg bs

  • 0
    TI__Guru* 81495 points

    Hello Peleg,

    The operation of the VCO1 at 7920MHz will simply not work. The varactor and tuning capacitors inside the PLL circuit will go out of range and the PLL will not lock. It is not a matter of KVCO, rather, the fundamental operation of the varactor and the tuning capacitors of the PLL design. Unfortunately, we cannot recommend you to use 7920MHz with the on-chip PLL mode of the DAC38RF93.

    -Kang