4-6

Rev. 1.0

5/6/98

US3012/3012A

TYPICAL APPLICATION

TYPICAL APPLICATION

SYNCHRONOUS OPERATION

(Dual Layout with RC5051)

Typical application of US3012/3012A in an on board DC-DC converter providing the Core supply for the Pentium II

microprocessor.

Table of components that need to be modified to make the dual layout work for US3012A* and RC5051.

Part #

R1

R2

R4

R7

R8

R9

R10

R11

C2

C5

C8

D1

RC5051

V

O

O

V

V

V

O

S

V

O

V

V

US3012A* S

V

S

O

S

O

V

O

V

V

V

O

S - Short

O - Open

V - See Unisem or Raytheon parts list for the value.

* Table also applies to the none "A" version of the part.

Note 1 : R8 can be replaced with shorting wire of #20 AWG or lower. This elliminates the expensive current

sense resistor that otherwise is needed with RC5051.

5V

12V

VID0

Power Good

3012app1-1.1

OutEn

Q2

VID1

VID2

VID3

VID4

L1

L2

C5

R2

C3

C4

C6

Q1

R3

R5

C7

R6

C11

C1

R7

C8

C2

R4

R9

R8

R12

R13

4

HDrv

LDrv

NC/Vccp

SS/Vref

CS+

Gnd

Vfb/

GndD

D3

D2

D4

D1

D0

US3012

En

PGd

CS-

V12

V5

18

12

19

5

20

9

15

10

11

14

1

3

2

16

7

13

8

6

17

NC/

GndA

NC/

GndP

Ct

R1

D1

R10

R11

C9

C10