LTC3717EGN#TRPBF Linear Technology, LTC3717EGN#TRPBF Datasheet - Page 15

• Manufacturer Part Number: LTC3717EGN#TRPBF
• Description: IC STEP-DWN CONTRLR SYNC 16-SSOP
• Manufacturer: Linear Technology

Specifications of LTC3717EGN#TRPBF

• Applications: Controller, DDR, QDR
• Voltage - Input: 4 ~ 36 V
• Number Of Outputs: 1
• Voltage - Output: 2 ~ 18 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIO S I FOR ATIO
(This is typically the case, since V
another DC/DC converter.) The ripple voltage will be only:
However, a 0A to 10A load step will cause an output
change of up to:
An optional 22 F ceramic output capacitor is included to
minimize the effect of ESL in the output ripple. The
complete circuit is shown in Figure 6.
PC Board Layout Checklist
When laying out a PC board follow one of the two sug-
gested approaches. The simple PC board layout requires
a dedicated ground plane layer. Also, for higher currents,
it is recommended to use a multilayer board to help with
heat sinking power components.
V
V
OUT(RIPPLE)
OUT(STEP)
C
L1: SUMIDA CEP125-0R68MC-H
C
IN
11k
470pF
ON
R3
, C
C
C1
0.1 F
0.01 F
511k
OUT1-2
C
R
= I
SS
ON
100pF
= I
= (4A) (0.013 ) = 52mV
C
20k
39k
R
R4
C2
: CORNELL DUBILIER ESRE181E04B
C
LOAD
U
L(MAX)
100k
R
(OPT)
0.1 F
(ESR) = (10A) (0.013 ) = 130mV
PG
U
1
2
3
4
5
6
7
8
(ESR)
RUN/SS
PGOOD
V
I
SGND
I
V
V
TH
ON
RNG
FB
REF
LTC3717
10
W
EXTV
IN
INTV
Figure 6. Design Example: 1.25V/ 10A at 250kHz
BOOST
PGND
V
SW
TG
BG
is derived from
CC
CC
CC
16
15
14
13
12
11
10
9
U
C
0.22 F
+
CMDSH-3
B
C
4.7 F
C
0.1 F
1
R
VCC
F
D
F
B
• The ground plane layer should not have any traces and
• Place C
• Place LTC3717 chip with pins 9 to 16 facing the power
• Use an immediate via to connect the components to
• Use compact plane for switch node (SW) to improve
• Use planes for V
V
it should be as close as possible to the layer with power
MOSFETs.
compact area. It may help to have some components on
the bottom side of the board.
components. Keep the components connected to pins
1 to 8 close to LTC3717 (noise sensitive components).
ground plane including SGND and PGND of LTC3717.
Use several bigger vias for power components.
cooling of the MOSFETs and to keep EMI down.
filtering and to keep power losses low.
EXT
M1
Si4874
M2
Si4874
5V
IN
, C
D2
B320A
D1
B320A
0.68 H
OUT
L1
, MOSFETs, D1 and inductor all in one
IN
and V
+
C
22 F
6.3V
X7R
C
270 F
2V
3717 F06a
OUT
IN
OUT1-2
2
to maintain good voltage
+
C
180 F
4V
C
22 F
6.3V
X7R
IN
2
OUT3
V
V
1.25V
LTC3717
IN
OUT
10A
= 2.5V
sn3717 3717fs
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