21

© 2007 Semtech Corp.

www.semtech.com

SC411

POWER MANAGEMENT

Figure 10: Connecting the Control and Power Sections

Q1

IRF7811AV

R4 7k87

L1 2u2

VOUT

1

VCCA

2

FB

3

PGD

4

VDDP

9

ILIM

10

LX

11

DH

12

U1

SC411

Q2

FDS6676S

0402

Phase nodes (black) to be copper islands (preferred) or wide copper traces. Gate drive traces (red) and phase node

traces (blue) to be wide copper traces (L:W < 20:1) and as short as possible, with DL the most critical.

VOUT

VBAT

PGOOD

5VSUS

VBAT

VOUT

5VSUS

0402

0402

0402

0402

0402

0402

0603

0603

0402

0603

SOD323

0402

0603

1210

7343

7343

L1 = 1.5uH Vishay IHLP 5050CE

VBAT = 8V to 20V

VOUT = 1.2V @ 10A

C6, C7 = 470uF / 15milli ohm

Sanyo POS Cap 2R5TPE470MF

D1

D1

+

C6

470u/15m

+

C6

470u/15m

C5

220p

C5

220p

R1

806k

R1

806k

Q2

IRF7832

Q2

IRF7832

C9

1uF

C9

1uF

R5

20k

R5

20k

R3

28k

R3

28k

C4

10u/25V

C4

10u/25V

+

C7

470u/15m

+

C7

470u/15m

VOUT

1

VCCA

2

FB

3

PGD

4

VDDP

9

ILIM

10

LX

11

DH

12

U1

SC411

U1

SC411

R2

10R

R2

10R

R4 7k15

R4 7k15

C3

0u1/25V

C3

0u1/25V

C8

1nF

C8

1nF

C10

1uF

C10

1uF

C1

0u1

C1

0u1

C2

2n2/50V

C2

2n2/50V

L1

1u5

L1

1u5

Q1

IRF7821

Q1

IRF7821

Figure 11: High Efficiency Design