16
LTC1435A
APPLICATIONS INFORMATION
WUU
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4. Does the (+) plate of C
IN
connect to the drain of the
topside MOSFET(s) as closely as possible? This capaci-
tor provides the AC current to the MOSFET(s).
5. Is the INTV
CC
decoupling capacitor connected closely
between
INTV
CC
and the power ground pin? This capaci-
tor carries the MOSFET driver peak currents.
6. Keep the switching node SW away from sensitive small-
signal nodes. Ideally the switch node should be placed
at the furthest point from the LTC1435A.
7. SGND should be exclusively used for grounding exter-
nal components on C
OSC
, I
TH
, V
OSENSE
and SFB pins.
8. If operating close to the minimum on-time limit, is the
sense resistor oriented on the radial axis of the induc-
tor? See Figure 8.
C
OSC
TG
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
LTC1435A
100pF
1000pF
C
C1
C
C2
R
C
C
OSC
C
SS
+
4.7µF
D
B
D1
C
B
0.1µF
C
IN
M1
M2
L1
R1
R2
R
SENSE
–
+
+
–
V
OUT
V
IN
1435A F10
BOLD LINES INDICATE
HIGH CURRENT PATHS
+
C
OUT
+
RUN/SS
I
TH
SFB
SGND
V
OSENSE
SENSE
–
SENSE
+
SW
V
IN
INTV
CC
BG
PGND
EXTV
CC
BOOST
I
TH
TG
1
2
3
5
6
10
11
15
12
14
16
13
78
C
OSC
43pF
C
C
1000pF
C
C2
220pF
50pF
R
C
10k
C
SS
0.1µF
SENSE
–
SENSE
+
LTC1435A
1000pF
+
4.7µF
C
F
0.1µF
D
B
CMDSH-3
0.22µF
M2
Si4410
D1
MBRS140T3
L1
3.3µH
M1
Si4410
R
SENSE
0.015Ω
4.7Ω
+
C
IN
10µF
30V
× 2
V
IN
4.5V TO 22V
+
C
OUT
820µF
4V
× 2
V
OUT
1.3V TO 2.0V
7A
PGND
BG
C
OSC
V
IN
V
OSENSE
BOOST
1435A TA07
SGND
RUN/SS
SW
INTV
CC
VID
0 1 2 3 GND
FROM µP
SENSE
LTC1706-19
FB
3
6
42187
5
V
CC
Intel Mobile CPU VID Power Converter
Figure 10. LTC1435A Layout Diagram
TYPICAL APPLICATIONS
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