SC486 Semtech Corporation, SC486 Datasheet - Page 22

• 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 switcher power section, the schematic in Figure 10 below shows the power section for VDDQ:
The highest di/dts occur in the input loop (highlighted in red) and thus this should be kept as small as possible. The
input capacitors should be placed with the highest frequency capacitors closest to the loop to reduce EMI. Use large
copper pours to minimize losses and parasitics. See Figure 11 below for an example.
POWER MANAGEMENT
2006 Semtech Corp.
Figure 11: Example VDDQ Power Section Layout
1
2
3
4
8
7
6
5
Figure 10: VDDQ Power Section and Input Loop
FDS6676S
Q1 IRF7811AV
S
S
S
G
D
D
D
D
D
D
D
D
G
S
S
S
Q2
8
7
6
5
1
2
3
4
VBAT
C5
2n2/50V
L1
22
1u5
C6
0u1/25V
+
C13
220u/15m
C7
10u/25V
+
C14
220u/15m
C8
10u/25V
VDDQ
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SC486