Datasheet

LTC3812-5
29
38125fc
APPLICATIONS INFORMATION
• Use compact plane for switch node (SW) to improve
cooling of the MOSFETs and to keep EMI down.
• Use planes for V
IN
and V
OUT
to maintain good voltage
fi ltering and to keep power losses low.
• Flood all unused areas on all layers with copper. Flooding
with copper will reduce the temperature rise of power
component. You can connect the copper areas to any
DC net (V
IN
, V
OUT
, GND or to any other DC rail in your
system).
When laying out a printed circuit board, without a ground
plane, use the following checklist to ensure proper opera-
tion of the controller.
• Segregate the signal and power grounds. All small
signal components should return to the SGND pin at
one point which is then tied to the PGND pin close to
the source of M2.
• Place M2 as close to the controller as possible, keeping
the PGND, BG and SW traces short.
•
Connect the input capacitor(s) C
IN
close to the pow-
er MOSFETs. This capacitor carries the MOSFET AC
current.
• Keep the high dV/dt SW, BOOST and TG nodes away
from sensitive small-signal nodes.
• Connect the INTV
CC
decoupling capacitor C
VCC
closely
to the INTV
CC
and SGND pins.
• Connect the top driver boost capacitor C
B
closely to
the BOOST and SW pins.
• Connect the bottom driver decoupling capacitor C
INTVCC
closely to the INTV
CC
and PGND pins.
Figure 15. 12V to 60V Input Voltage to 5V/6A
PGOOD
FCB
PGOOD
V
RNG
I
TH
SGND
V
FB
SGND PGND
PGND
RUN/SS
I
ON
C
ON
100pF
C
SS
1000pF
V
IN
12V TO 60V
V
OUT
5V
6A
M3
ZXMN10A07F
C
C2
47pF
R
C
200k
R
FB2
1.89k
R
FB1
10k
LTC3812-5
EXTV
CC
TG
SW
BG
PGND
INTV
CC
NDRV
BOOST
38125 F15
C
B
0.1μF
C
DRVCC
0.1μF
C
VCC
1μF
R
ON
110k
150k
100k
R
NDRV
100k
D
B
BAS19
M1
Si7850DP
M2
Si7850DP
D1
B1100
C
OUT1
270μF
6.3V
C
OUT2
10μF
6.3V
L1
7.7
μH
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
C
C1
5pF
C
IN1
68μF
100V
C
IN2
1μF
100V