Use RoboClockII To Multiply A Frequency

Question: How can a frequency be multiplied using RoboClockII?

 

Answer:

RoboClock is a Phase-Locked Loop (PLL) based clock buffer with the added flexibility of programmable output skew and divide. The PLL is a circuit that synchronizes an output generated by an internal oscillator with the reference (REF) input. If a divided output is applied to the feedback (FB) input, it will cause the internal VCO (voltage controlled oscillator) to operate at the divided factor times the reference frequency.

For example, if one is a 20-MHz reference input and an output that has been configured for divide-by-two (/2) is connected to the feedback input, the internal VCO has to operate at twice the reference frequency in order to align the REF and FB inputs. Thus, applying a divided feedback configures RoboClock as a frequency multiplier.