LTC3633 LINER [Linear Technology], LTC3633 Datasheet - Page 22

• Manufacturer Part Number: LTC3633
• Description: Dual Channel 3A, 15V Monolithic Synchronous Step-Down Regulator
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
LTC3633
A 47μF ceramic capacitor should be suffi cient for channel
1. Solving the same equation for channel 2 (using 5% of
V
the closest standard value).
C
Solving this equation for channel 2 results in an RMS
input current of 1.3A. Decoupling each V
a 47μF ceramic capacitor should be adequate for most
applications.
22
OUT
IN
I
RMS
should be sized for a maximum current rating of:
for V
=
3
DROOP
A
1 8 13 2
) results in 27μF of capacitance (22μF is
.
3.3V AT 3A
V
V
(
OUT2
12V
C
V
13 2
47μF
OUT2
22μF
IN
C
162k
×2
IN
.
.
R5
V
V
−
1 8
.
1μH
L2
V
54.9k
R4
)
=
0.1μF
1
12.1k
A
R3
IN
Figure 8. Design Example Circuit
input with
RUN1
RUN2
RT
TRACKSS2
PGOOD2
BOOST2
SW2
V
V
ON2
FB2
SGND
V
IN2
LTC3633
PGND
V
MODE/SYNC
IN1
Lastly, the feedback resistors must be chosen. Picking R1
and R3 to be 12.1k, R2 and R4 are calculated to be:
The fi nal circuit is shown in Figure 8.
TRACKSS1
PHMODE
PGOOD1
BOOST1
INTV
R2 = (12.1k) •
R4 = (12.1k) •
V2P5
V
ITH1
ITH2
SW1
V
ON1
FB1
CC
R1
12.1k
0.1μF
24.3k
C2
2.2μF
R2
1.8V
0.6V
3.3V
0.6V
0.68μH
L1
– 1 = 24.2k
– 1 = 54.5k
C
47μF
OUT1
V
1.8V AT 3A
OUT1
3633 F08
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