iru3033 International Rectifier Corp., iru3033 Datasheet - Page 6

• Manufacturer Part Number: iru3033
• Description: 8-pin Pwm Switcher And Linear Controller Ic
• Manufacturer: International Rectifier Corp.

IRU3033
TYPICAL APPLICATION
5V to 3.3V for Pentium Application with AGP or Pentium II Application without ATX power supply Dual
mode Operation between Switching or Linear mode.
Figure 4 - This unique application of IRU3033 allows the designer to switch between Linear or Switching mode of
operation using a single IC. This circuit has the flexibility to be used for low current operation in Linear mode for cost
reasons and yet be able to operate in the Switching mode if the load current increases and the heat generated by
the Linear operation will be an issue.
6
12V
5V
The table below describes the components that will be effected for the two modes of operation.
R10
C1
R9
L1
Mode of Operation
Switching
Linear
R1A
C8
C2
V = See parts list for value
Q2
R1B
V
Drv1
1 2 ( S W )
V
L1
V
S
12
R13
C3
L2
V
S
Drv2
V
U1
FB1
D1
V
O
V
V
www.irf.com
C4
FB2
C4
Gnd
H Y S T
V
O
R2
R3
C9
C5
V
O
R1A
S = Short
O
V
D1
R1B
C5
V
O
R2
V
O
R3
O = Open
V
O
R4
V
V
L2
R5
R4
R5
V
O
R6
R7
R6
V
V
R7
O
V
C7
V
OUT
07/17/02
Rev. 1.7