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LT3471 - Calculating C6 For SW2 Output

The LT3471 datasheet discusses calculation of Cpl for the SW1 output on pages 7 through 8 of the datasheet.  Figure 2 on page 8 of the datasheet shows Cpl with a value of 33pF (presumably calculated as discussed on pages 7 and 9 of the datasheet based on the R3 value of 90.9k).  However, C6 (in parallel with R1 with a value of 105k) in Figure 2 on page 8 of the datasheet, and the calculation thereof, is not discussed in either the datasheet or the eval board manual.  How is the value of C6 (75pF in Figure 2) calculated?

Thanks,

Bryan

  • Hi Bryan,

    Calculated values are approximations. The actual values needed should be determined through measurement. The 75pF shown was determined through bench testing. Please use value which matches application the closest and then test and adjust this value up and down slightly to determine best value for the application.