US2076
TYPICAL APPLICATION
L1
I / O
5V
C1
C6
R6
R7
Vin
Vout
Vfb2
7
6
5
4
3
2
1
5V
CPU
R8
D2
Gnd
Vfb1
V12
Drv
U1
Vcc2 Det
Core
L2
C2
R1
C4
Q2
C7
R4A
R5E
R4B
2076app2-1.2
12V
C3
R5A
R5B
R5C
R5D
R2
D1
JP1
1
2
3
4
5
6
7
8
Figure2- Typical application of US2076 in a flexible motherboard with the 4 bit VID output voltage selection. This circuit
uses a single jumper that programs the output voltage in 16 steps with 0.1V steps from 2V to 3.5V, designed for Intel P55ä ,P54ä ,
AMD K5 & K6ä as well as Cyrix M1ä and M2ä applications. The Vcc2Det pin automatically shuts down the I/O when a single plane
processor is dropped in the socket.
Ref Desig Description
Qty
Part #
Manufacturer
U1
Q1
D1
LDO/Switcher IC
1
US2076CT (TO220)
US2076CM (TO263) (note 1)
IRL3303 (TO220)
IRL3103S (TO263) (note 1)
MBR1045CT (TO220)
Unisem
MOSFET
1
1
International
Rectifier
Motorola
Schottky Diode
MBRB1545CT (TO263) (note1)
1N4148
Core:T50-18,L=4 uH
D2
L2
Diode, GP
Inductor
1
1
Micro Metal
(core)
Turns: 10T, 18 AWG
L1
R1
R2
Inductor
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4
1
1
1
L=2 uH
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Heat Sink
Heat Sink
Heat Sink
22 ohm,5%, SMT 1206 size
10 ohm, 5%, SMT 1206 size
806 ohm,1%, SMT 0805 size
90.9 kohm,1%, SMT 0805 size
1.24 kohm,1%, SMT 0805 size
2.49 kohm,1%, SMT 0805 size
4.99 kohm,1%, SMT 0805 size
10 kohm,1%, SMT 0805 size
1.30 kohm,1%, SMT 0805 size
ohm,1%, SMT 0805 size
R4A
R4B
R5A
R5B
R5C
R5D
R5E
R6
R7
R8
C3
C1
C4
C2
C6
C7
HS1
HS2
HS3
ohm,1%, SMT 0805 size
10 kohm,5%, SMT 0805 size
1 uF,Ceramic, SMT 0805 size, Z5U
EEUFA1A681L, 680uF,10V, Elect
470pF,Ceramic, SMT 0805 size
6MV1500GX, 1500uF,6.3V, Elect
EEUFA1A681L, 680uF,10V, Elect
6MV1500GX, 1500uF,6.3V, Elect
For MOSFET , 577002
Panasonic
Sanyo
Panasonic
Sanyo
Aavid
Aavid
Aavid
For Schottky Diode , 577002
For US2076 , 507222 (I/O Load Current<5A)
576602 (I/O Load Current< 3.5A)
Note 1: For the applications where it is desirable to eliminate the heat sink, the US2076CM for U1 when load current is
less than 1.5A, the IRL3103S for Q2 and MBR1545CT for D1 in TO263 packages with minimum of 1" square copper pad
can be used.
Rev. 1.3
4/26/98
4-4
UNISEM [ UNISEM ]
