YB1680
1.5MHz, 600mA Synchronous Step-Down Converter
approximately 35% of the maximum load
switching frequency. Ceramic capacitors
with X5R or X7R dielectrics are
recommended due to their low ESR and
high ripple current. The output ripple VOUT
is determined by:
current 600mA, or ΔIL = 210mA.
For output voltages above 2.0V, when
light-load efficiency is important, the
minimum recommended inductor is 2.2μH.
For optimum voltage-positioning load
transients, choose an inductor with DC
series resistance in the 50mΩ to 150mΩ
range. For higher efficiency at heavy loads
(above 200mA), or minimal load regulation
(but some transient overshoot), the
resistance should be kept below 100mΩ.
The DC current rating of the inductor
should be at least equal to the maximum
load current plus half the ripple current to
prevent core saturation (600mA+105mA).
Input Capacitor Selection
The input capacitor reduces the surge
current drawn from the input and switching
noise from the device. The input capacitor
impedance at the switching frequency shall
be less than input source impedance to
prevent high frequency switching current
passing to the input. A low ESR input
capacitor sized for maximum RMS current
must be used. Ceramic capacitors with
X5R or X7R dielectrics are highly
recommended because of their low ESR
and small temperature coefficients. A 4.7μF
ceramic capacitor for most applications is
sufficient.
Output Capacitor Selection
The output capacitor is required to keep the
output voltage ripple small and to ensure
regulation loop stability. The output
capacitor must have low impedance at the
YB1680 Rev.1.0
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YOBON [ YOBON TECHNOLOGIES,INC. ]
