JAJSNW0C July 2023 – April 2024 TPSM8287A06 , TPSM8287A12 , TPSM8287A15
PRODMIX
If the converter remains in regulation, the minimum required output capacitance is given by:
If the converter loop saturates, the minimum output capacitance is given by:
In this case, choose COUT(min) = 1094 µF as the larger of the two values for the output capacitance.
Table 9-3 lists the output capacitors chosen. 2 × 47-µF capacitors are placed close to each of the four modules, giving a minimum effective capacitance of about 27 µF each. Five 220-µF capacitors and five 47-µF are placed near the load to approximate the total decoupling capacitance required by a typical load. Each of the 220-µF capacitors yield about 138 µF of effective capacitance. Together, the 1041 µF of effective capacitance is very close to the required minimum value calculated above. For further calculations, use COUT = 1041 µF.
Equation 48 checks that most of the output capacitance is placed at the load. If the ratio is less than 1, increase the capacitance at the load or place the device, output capacitance, and load next to each other such that there is no separation between the output capacitances.