SC1480A Ver la hoja de datos (PDF) - Semtech Corporation

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componentes Descripción

Fabricante

SC1480A

DDR and DDR Memory VTT power Supply Controller

Semtech Corporation 

SC1480A

POWER MANAGEMENT

Application Information (Cont.)

As shown below, .B and VSSA should be routed as a differential pair to the output capacitor.

C7

0u1

0402

R6

10k0

0402

C2

1u

0603

C8

1n

0402

R7

10R

0402

C9

1u

0603

U1

1 REFIN

2 TON

3

REFOUT

4 VCCA

5 FB

6 PGD

7

VSSA

SC1480A

BST 14

DH 13

12

LX

ILIM 11

VDDP 10

DL 9

8

PGND

R8 0R

0402

VTT

C6

+

220u/15mOhm

7343

VSSA

FB

.igure 6: Differential Routing of .eedback and Ground Reference Traces

Next, looking at the power section, the schematic in .igure 7 below shows the power section. The highest di/dts

occur in the input loop (highlighted in red) and thus this loop should be kept as small as possible.

VBAT

Q1 5 6

FDS6982S

4

3

8

2

1

C4

2n2

0402

C3

0u1

0603

C1

10u

1210

L1 2u2

7

VTT

2525

C6

+

R8 0R

0402

220u/15mOhm

7343

.igure 7: Power Section and Input Loop

The input capacitors should be placed with the highest frequency capacitors closest to the loop to reduce EMI. Use

large copper pours to minimize parasitics and losses. See .igure 8 on Page 17 for an example.

 2003 Semtech Corp.

16

www.semtech.com

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