ZHCSHA3D NOVEMBER 2009 – March 2018 TPS40303 , TPS40304 , TPS40305
PRODUCTION DATA.
The selection of the output capacitor is typically driven by the output transient response. Equation 5 and Equation 6 overestimate the voltage deviation to account for delays in the loop bandwidth and can be used to determine the required output capacitance.
If VIN(min)> 2 × VOUT, use overshoot (Equation 5) to calculate minimum output capacitance. If VIN(min)< 2 × VOUT, use undershoot (Equation 6) to calculate minimum output capacitance.
With a minimum capacitance, the maximum allowable ESR is determined by the maximum ripple voltage and is approximated by Equation 8.
Two 0805, 22-µF, 6.3-V, X5R ceramic capacitors are selected to provide more than 35 µF of minimum capacitance and less than 7 mΩ of ESR (2.5 mΩ each).