SLUSD89B February 2019 – November 2019 BQ25887
PRODUCTION DATA.
The input capacitor should have enough ripple current rating to absorb input switching ripple current. The worst case RMS ripple current occurs when duty cycle is 0.5. If the converter does not operate at 50% duty cycle, then the worst case capacitor RMS current IPMID occurs where the duty cycle is closest to 50% and can be estimated by
A low ESR ceramic capacitor such as X7R or X5R is preferred for input decoupling capacitor and should be placed close to the PMID and GND pins of the IC. Voltage rating of the capacitor must be higher than normal input voltage level. 25-V rating or higher capacitor is preferred for up to 5-V input voltage. A minimum 10-μF capacitor is suggested for up to 3.3-A input current. Keep in mind, long impedance cable would cause significant voltage drop with higher inrush current. For optimal performance, 44-uF cap on PMID is recommended. In addition, a minimum 1-μF capacitor is suggested at VBUS pin.