Datasheet

LTC3775
27
3775fa
APPLICATIONS INFORMATION
The worst-case peak inductor current based on a sense
resistor tolerance of ±1% is
I
L(SAT)

110μA • 732
2.97m

= 27.1A
The input RMS current is highest at V
IN(MIN)
= 5V and
I
OUT(MAX)
= 15A:
IA
VV V
V
A
RMS
≈
()
=15
12 5 12
5
64
.–.
.
C
IN
is chosen for an RMS current rating of >6.4A at 85°C.
For the output capacitor, two low ESR OS-CON capacitors
(470µF/5m each) are used to minimize output voltage
changes due to inductor current ripple and load steps.
The ripple voltage will be:
V
OUT( RI PPLE)
= 6.4A •
0.005
2
+
1
8 • 500kHz • 470μF • 2






=17.7mV
However, a 0A to 15A load step will cause an output volt-
age change of at least:
∆V
OUT(STEP)
= (15A)(0.0025) = 37.5mV