SC486 Semtech Corporation, SC486 Datasheet - Page 24

• Manufacturer Part Number: SC486
• Description: Complete DDR1/2/3 Memory Power Supply
• Manufacturer: Semtech Corporation

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Layout Guidelines (Cont.)
Next looking at the VTT output:
The output capacitors should be connected right at the chip, on the same side as the chip and right across the pins.
The input capacitor may be placed on the opposite side, if desired. See Figure 14 below:
Output capacitors C15 and C16 are placed across the device pins, and connect to the ground plane using multiple
vias. Input capacitor C17 connects directly to the device pins and connects to the ground plane using two vias. Note
that PGND1, PGND2 and VSSA all connect to the pad under the device, which should also connect to the ground
plane using multiple vias.
POWER MANAGEMENT
2006 Semtech Corp.
Figure 14: Example VTT Output Component Placement and Starred Ground
VDDQ
VTT
C15
10u
Figure 13: VTT Output
C16
10u
24
C17
1u
11
10
14
15
12
13
16
17
3
2
6
8
9
5
4
U1
VTTEN
VDDQS
TON
FB
REF
COMP
VTTS
VCCA
VSSA
VTT
VTT
VTTIN
VTTIN
PGND2
PGND2
EN/PSV
PGND1
VDDP
SC486
PGD
ILIM
BST
DH
DL
LX
7
1
24
23
21
22
19
20
18
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SC486