US3005CW UNISEM [UNISEM], US3005CW Datasheet - Page 8

• Manufacturer Part Number: US3005CW
• Description: 5 BIT PROGRAMMABLE SYNCHRONOUS BUCK CONTROLLER IC WITH DUAL LDO CONTROLLER
• Manufacturer: UNISEM [UNISEM]

US3004,US3005
4-8
TYPICAL APPLICATION
Pentium with AGP
TYPICAL APPLICATION
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.
VID4
VID3
VID2
VID1
VID0
C1
3.3V
12V
5V
C13
C2
R18
13
1
C3
C4
L1
Ct
SS
V12
D4
12
15
C5
V5
D3
16
5
C6
R1
CS+
D2
17
8
R2
HDrv
US3004
Q1
D1
18
9
CS-
D0
19
7
R3
LDrv
PGd
11
C8
6
R5
3.3V
Vfb2
Gnd
10
4
Q2
Power Good
Vfb3
Lin2
14
20
Vfb1
Lin1
C7
R4
C9
R16
2
3
L2
R9
R12
R11
R17
C16
R13
Q3
Q4
C15
C14
C10
Vout 3
R14
R15
R7
R8
3004app3-1.4
C11
C12
3.3V
Rev. 1.2
12/8/00