ELM620BA 1.4MHz
high efficiency synchronous PWM step up DC/DC converter
3) Output and input capacitor selection
Low ESR (equivalent series resistance) capacitors should be used to minimize the output voltage ripple. Mul-
tilayer ceramic capacitors are an excellent choice, as they have extremely low ESR and are available in small
footprints. A 4.7μF to 22μF output capacitor is sufficient for most applications; larger values up to 22μF may be
used to obtain extremely low output voltage ripple and improve transient response. An additional phase lead ca-
pacitor may be required with output capacitors larger than 10μF to maintain acceptable phase margin. X5R and
X7R dielectric materials are preferred for their ability to maintain capacitance over wide voltage and tempera-
ture ranges.
Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. It
follows that ceramic capacitors are also a good choice for input decoupling and should be located as closely as
possible to the device. A 10μF input capacitor is sufficient for virtually any application. Larger values may be
used without limitations.
■Marking
SOT-26
a to e : Assembly lot No.
a b c d e
A to Z (I, O, X excepted) and 0 to 9
�
Rev.1.0
10 - 6
ELM-TECH [ ELM Technology Corporation ]
