JAJSVO7 November 2024 TPS923650
PRODUCTION DATA
An input capacitor is required to reduce the surge current drawn from the input supply and the switching noise coming from the device. Electrolytic capacitors are recommended for energy storage. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, it is recommended to place a 10μF capacitor along with a 0.1µF capacitor from VIN to GND to provide high-frequency filtering. The input capacitor voltage rating must be greater than the maximum input voltage. Use the equation below to calculate the input ripple voltage, where ESRCIN is the ESR of input capacitor, and KDR is the derating coefficient of ceramic capacitance at the applied DC voltage.
In this design, a 10µF, 50V electrolytic capacitor, a 22µF, 50V X7R ceramic capacitor and a 0.1µF, 50V X7R ceramic capacitor are chosen, yielding around 270mV input ripple voltage.