LTC3831EGN-1 Linear Technology, LTC3831EGN-1 Datasheet - Page 17

• Manufacturer Part Number: LTC3831EGN-1
• Description: IC CTRLR SW REG SYNC DDR 16SSOP
• Manufacturer: Linear Technology

Specifications of LTC3831EGN-1

• Applications: Controller, DDR
• Voltage - Input: 3 ~ 8 V
• Number Of Outputs: 1
• Voltage - Output: 0.4 ~ 4 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
Table 2 shows the suggested compensation component
value for 1.5V to 0.75V applications based on the 470 F
Sanyo POSCAP 4TPB470M output capacitors.
Table 3 shows the suggested compensation component
values for 1.5V to 0.75V applications based on 1500 F
Sanyo MV-WX output capacitors.
Table 2. Recommended Compensation Network for 1.5V to
0.75V 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
C1
C
C
C
OUT
R
1410
2820
4700
1410
2820
4700
1410
2820
4700
C
( F)
U
C
NC
U
2.2 F
SS
R
GND
C
5.6
12
20
12
27
43
24
51
93
(k )
FREQSET
SHDN
COMP
SS
GND
Figure 8. Typical Schematic Showing Layout Considerations
V
V
CC
CC
LTC3831-1
W
C
C
PV
PGND
3.3
3.3
2.2
3.3
1.5
1.0
1.5
1.0
3.3
PV
(nF)
I
CC2
MAX
CC1
I
BG
TG
R
R
FB
FB
+
–
PV
U
CC
PGND
C1 (pF)
68
33
22
33
15
10
15
10
10
4.7 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
LTC3831-1. These items are also illustrated graphically in
the layout diagram of Figure 8. The thicker lines show the
high current paths. Note that at 5A current levels or above,
current density in the PC board itself is a serious concern.
Table 3. Recommended Compensation Network for 1.5V to
0.75V 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
/V
Q1
Q2
DDQ
PGND
C
OUT
4500
6000
9000
4500
6000
9000
4500
6000
9000
( F)
OPTIONAL
MBRS340T3
MBRS340T3
R
+
C
130
15
18
30
30
39
62
62
82
(k )
C
IN
L
O
LTC3831-1
C
C
2.2
2.2
+
(nF)
1
1
1
1
1
1
1
38311 F08
C
V
OUT
OUT
C1 (pF)
17
120
82
56
56
33
27
27
22
10
38311f