US3033 UNISEM, US3033 Datasheet - Page 7

• Manufacturer Part Number: US3033
• Description: PWM SWITCHER & LINEAR CONTROLLER IC
• Manufacturer: UNISEM

Note 1: For the applications where it is desirable to eliminate the heat sink, the IRL3103S for Q2 and MBR1545CT for D2 in TO263
packages with minimum of 1" square copper pad can be used.
TYPICAL APPLICATION
TYPICAL APPLICATION
5V to 3.3V for Pentium Application with AGP or Pentium II Application without ATX power supply
Switching mode Operation.
Rev. 1.5
1/14/99
Ref Desig
U1
Q2
D1
L2
L1
R1
R9
R2
R3
R4
R5
C1,2
C3
C4
C5
C7
C8
HS1
HS2
generate a low cost 5V to 3.3V for either Pentium application with AGP socket or in Pentium II applications where it is desirable to
generate an accurate on board 3.3V supply.
12V
Description
LDO/Switcher IC
MOSFET
Schottky Diode
Inductor
Inductor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Heat Sink
Heat Sink
Figure4- The circuit in figure 4 is the application of the US3033 in a switching mode only. This circuit can be used to
5V
R9
C1
L1
C8
Qty
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
C2
R1
C3
Drv1 V12swVfb1 Vhyst
V12
Q2
8
1 2 3 4
US3033CS ( 8 pin SOIC)
IRL3303 (TO220)
IRL3103S (TO263) (note 1)
MBR1045CT (TO220)
MBRB1545CT (TO263) (note1)
Core:T50-18,L=4 uH
Turns: 10T, 18 AWG
L=2 uH
22 ohm,5%, SMT 1206 size
10 ohm,5%, SMT 0805 size
10 ohm, 5%, SMT 1206 size
249 kohm,1%, SMT 0805 size
1 kohm,1%, SMT 0805 size
576 ohm,1%, SMT 0805 size
6MV1500GX, 1500uF,6.3V, Elect
1 uF,Ceramic, SMT 0805 size
470 pF,Ceramic, SMT 0805 size
10 pF,Ceramic, SMT 0805 size
6MV1500GX, 1500uF,6.3V, Elect
1 uF,Ceramic, SMT 0805 size
For MOSFET , 577002
For Schottky Diode , 577002
Drv2
7
U1
Vfb2
6
C4
Gnd
5
R2
R3
Part #
D1
C5
3033app4-1.2
L2
R4
R5
C7
Manufacturer
Rectifier
Micro Metal
International
Motorola
Vout
Unisem
(core)
Sanyo
Sanyo
Sanyo
Sanyo
Aavid
Aavid
US3033
4-7