The capacitor placed on the SS/REFIN pin can be
used to extend the soft-start time past the internal 1.5-ms soft start. This example
uses a 2-ms soft start time and the required external capacitance can be calculated
with Equation 28. In this example, a 22-nF capacitor is used.
Equation 28. ![TPS54J060](/ods/images/SLVSES4D/GUID-97C585A2-0B46-4100-A828-F82C8B7A86CB-low.gif)
Note: A minimum capacitor value of 1 nF is required at the SS/REFIN pin to help bypass noise.
Also, the SS/REFIN capacitor must use the AGND pin for the ground. Note, any CSS
calculation that uses a soft-start time of less than 1.5 ms will be ignored by the internal
soft-start time circuit. Therefore, selecting a capacitor less than or equal to 15 nF will
result in the internal default 1.5 ms soft-start time.