4-8

Rev. 1.2

12/8/00

US3004,US3005

TYPICAL APPLICATION

TYPICAL APPLICATION

Pentium with AGP

Figure 3- Typical application of US3004 in a Pentium with AGP where the power dissipation of the 3.3V

linear regulator is equally distributed between Q3 and Q4 pass transistors. This equal distribution is

possible by accurately regulating the first regulator using the US3004 linear controller and its internal 1%

reference voltage while the second controller regulates the output of the first regulator from 4.17V to

3.3V, thereby distributing the power dissipation equally.

VID0

Power Good

3004app3-1.4

3.3V

C9

Q4

VID1

VID2

VID3

VID4

Q3

R7

R8

C11

C12

R5

C8

C1

C2

3.3V

R9

R11

C15

C14

R14

R15

12

HDrv

LDrv

Ct

SS

CS+

Gnd

Vfb3

D3

D2

D4

D1

D0

PGd

US3004

Lin1

Vfb1

CS-

V12

V5

Vfb2

Lin2

15

5

16

8

17

9

18

7

19

11

6

10

4

14

20

3

2

13

1

Vout 3

5V

12V

3.3V

Q2

L1

L2

C5

R1

C3

C4

C6

Q1

R2

R3

C7

R4

C10

C13

R12

R16

R17

R13

C16

R18