Datasheet

LTC3703
29
3703fc
applicaTions inForMaTion
5. Place the small-signal components away from high
frequency switching nodes (BOOST, SW, TG, and BG).
In the layout shown in Figure 20, all the small-signal
components have been placed on one side of the IC
and all of the power components have been placed on
the other. This also helps keep the signal ground and
power ground isolated.
6. A separate decoupling capacitor for the supply, V
CC
,
is useful with an RC filter between the DRV
CC
supply
and V
CC
pin to filter any noise injected by the drivers.
Connect this capacitor close to the IC, between the
V
CC
and GND pins and keep the ground side of the V
CC
capacitor (signal ground) isolated from the ground side
of the DRV
CC
capacitor (power ground).
7. For optimum load regulation and true remote sensing,
the top of the output resistor divider should connect
independently to the top of the output capacitor (Kelvin
connection), staying away from any high dV/dt traces.
Place the divider resistors near the LTC3703 in order
to keep the high impedance FB node short.
8. For applications with multiple switching power con-
verters connected to the same input supply, make
sure that the
input filter capacitor for the LTC3703
is
not shared with other converters. AC input current
from another converter could cause substantial input
voltage ripple, and this could interfere with the opera-
tion of the LTC3703. A few inches of PC trace or wire
(L ≅ 100nH) between C
IN
of the LTC3703 and the actual
source V
IN
should be sufficient to prevent input noise
interference problems.
LTC3703
MODE/SYNC
f
SET
COMP
FB
I
MAX
INV
RUN/SS
GND
V
IN
BOOST
TG
SW
V
CC
DRV
CC
BG
BGRTN
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
C
C1
C
IN
C
C2
C
C3
R
C1
R
C2
R1
R2
R
F
R
MAX
R
SET
C
B
V
IN
M1
M2
L1
D1
V
OUT
C
OUT
D
B
V
CC
C
SS
3703 F18
C
DRVCC
X5R
C
VCC
X5R
+
+
+
–
Figure 20. LTC3703 Buck Converter Suggested Layout