ZHCSHA3D NOVEMBER 2009 – March 2018 TPS40303 , TPS40304 , TPS40305
PRODUCTION DATA.
The input voltage ripple is divided between capacitance and ESR. For this design VRIPPLE(cap) = 150 mV and VRIPPLE(esr) = 150 mV. The minimum capacitance and maximum ESR are estimated by Equation 11.
The RMS current in the input capacitors is estimated by Equation 13.
Two 1210, 10-µF, 25-V, X5R ceramic capacitors with approximately 2-mΩ of ESR and a 2.5-A RMS current rating each are selected. Higher voltage capacitors are selected to minimize capacitance loss at the DC bias voltage to ensure the capacitors allow sufficient capacitance at the working voltage.