Charge Pump Setting Handling by CyClocksRT While Configuring CY22150 | Cypress Semiconductor
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Charge Pump Setting Handling by CyClocksRT While Configuring CY22150
How does the CyClocksRT software calculate the Charge Pump settings while configuring the jedec file for the CY22150?
The CyClocksRT uses a proprietary algorithm to optimize the charge pump value. The table in the datasheet will give you guaranteed PLL stability, but will not necessarily be the optimum solution. We recommend referencing the CyClocksRT charge pump value for critical configurations.
The datasheet values are set to cover a wide range of possible P values, while CyClocksRT knows exactly which P value you will be using.
The datasheet table chooses the lowest charge pump value acceptable for a specific range of P values; the lowest value will give you the most stability margin.
CyClocksRT goes from the highest charge pump setting and calculates the loop bandwidth, if the phase detector frequency, which is equal to VCO/P, is 5 times greater than the calculated bandwidth it will stop searching. Otherwise it will go to the next lower charge pump setting and go through the calculation again.