LTC3831 LINER [Linear Technology], LTC3831 Datasheet - Page 17

• Manufacturer Part Number: LTC3831
• Description: High Power Synchronous Switching Regulator Controller for DDR Memory Termination
• Manufacturer: LINER [Linear Technology]

APPLICATIO S I FOR ATIO
Table 2 shows the suggested compensation component
value for 2.5V to 1.25V applications based on the 470 F
Sanyo POSCAP 4TPB470M output capacitors.
Table 3 shows the suggested compensation component
values for 2.5V to 1.25V applications based on 1500 F
Sanyo MV-WX output capacitors.
Table 2. Recommended Compensation Network for 2.5V to
1.25V Applications Using Multiple Paralleled 470 F Sanyo
POSCAP 4TPB470M Output Capacitors
L1 ( H)
1.2
1.2
1.2
2.4
2.4
2.4
4.7
4.7
4.7
4.7 F
C1
C
C
C
OUT
R
1410
2820
4700
1410
2820
4700
1410
2820
4700
C
+
( F)
U
GND
C
NC
U
1 F
SS
R
GND
C
120
6.8
15
22
15
36
47
33
68
(k )
FREQSET
SHDN
COMP
SS
Figure 10. Typical Schematic Showing Layout Considerations
GND
V
CC
LTC3831
100
W
C
C
PV
PGND
3.3
3.3
1.5
3.3
4.7
10
10
22
10
PV
(nF)
I
CC2
MAX
CC1
I
BG
TG
R
R
FB
FB
+
–
PV
U
CC
C1 (pF)
PGND
33
33
33
33
10
10
10
10
10
1 F
0.1 F
10k
LAYOUT CONSIDERATIONS
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of the
LTC3831. These items are also illustrated graphically in
the layout diagram of Figure 10. The thicker lines show the
high current paths. Note that at 5A current levels or above,
Table 3. Recommended Compensation Network for 2.5V to
1.25V Applications Using Multiple Paralleled 1500 F Sanyo
MV-WX Output Capacitors
L1 ( H)
1k
1.2
1.2
1.2
2.4
2.4
2.4
4.7
4.7
4.7
V
IN
Q1
Q2
PGND
C
OUT
4500
6000
9000
4500
6000
9000
4500
6000
9000
( F)
OPTIONAL
MBRS340T3
MBRS340T3
R
+
C
100
150
20
27
43
51
62
82
82
(k )
C
IN
L
O
C
C
0.47
0.47
1.5
3.3
+
(nF)
1
1
1
1
1
LTC3831
3830 F11
C
V
OUT
OUT
C1 (pF)
17
120
82
56
56
33
27
33
15
15
3831f