UNISEM US2075

US2075
PWM SWITCHER CONTROLLER & 7.5A
LOW DROPOUT REGULATOR COMBO
PATENT PENDING
FEATURES
DESCRIPTION
The US2075 eliminates the need for a
seperate switching controller IC
Minimum part count allows lower system cost
Fixed 3.30V/7.5A LDO on board
On board MOSFET driver
Fastest transient response of any controller
method. ( 0 to 100% Duty Cycle in 100 nS )
1% internal voltage reference
Internal Thermal shutdown
Internal Under Voltage Lockout protects
MOSFET during start-up
APPLICATIONS
Dual supply low voltage processor applications,
such as: P55C,CYRIX M2, POWER PC and
AMD
The US2075 is a dual function IC combining a switching
controller and a 7.5A low dropout regulator all in a compact 7 pin TO220 and TO263 surface mount packages providing a total solution for dual supply processor applications such as an Intel P55C , AMD K6,
as well as Cyrix 6X86L and the M2processors.
Typically in these applications a dual supply regulator
converts 5V to 3.3V for I/O supply and a jumper programmable supply of 2.8V to 3.5V for CORE supply .The
linear regulator portion in the US2075 is a fixed 3.30V
output and has a minimum of 7.5A current capability
designed to provide ample current for most applications
while the switching regulator controller uses the 5V supply to power the controller and the 12V supply to drive
the power MOSFET, allowing a low cost N- MOS switch
to be used. The IC also includes an error comparator for
fastest transient response, a precise voltage reference
for setting the output voltage as well as a direct drive of
the MOSFET for the minimum part count.
TYPICAL APPLICATION
5V
V5
7
Vout
Vhyst
6
5
Gnd
4
Vfb
V12
3
2
Drv
1
US2075
3.30V / 7.5A
2.8V / 10A
2075ap1a-1.0
12V
Typical application of US2075 in a flexible mother board designed for Intel P55,P54
AMD K5,K6 as well as Cyrix M1 and M2 applications.
Notes: P54C,P55C are trade marks of Intel Corp. K5 & K6 are trade marks of AMD corp. Cyrix 6X86L,M1,M2 are trade marks of Cyrix
Corp. Power PC is trade mark of IBM Corp.
PACKAGE ORDER INFORMATION
Tj (°C)
0 TO 125
Rev. 1.2
4/26/98
7 PIN PLASTIC
TO220 (T)
US2075CT
7 PIN PLASTIC
TO263 (M)
US2075CM
4-1
US2075
ABSOLUTE MAXIMUM RATINGS
12V Supply Voltage ............................................................. 14V
5V Supply Voltage .............................................................. 7V
LDO Power Dissipation .................................... Internally Limited
FB Pin Voltage........................................................
-0.3V to 5V
Storage Temperature Range ................................. -65 TO 150°C
Operating Junction Temperature ............................... O TO 150°C
PACKAGE INFORMATION
7 PIN PLASTIC TO220 (T)
7 PIN PLASTIC TO263 (M)
FRONT VIEW
FRONT VIEW
7
6
5
4
3
2
1
7
6
5
4
3
2
1
V5
Vout
Vhyst
Gnd
Vfb
V12
Drv
θJT=2.7°C/W θJA=60°C/W
V5
Vout
Vhyst
Gnd
Vfb
V12
Drv
θJA=35°C/W for 1" Square pad
ELECTRICAL SPECIFICATIONS
Unless otherwise specified the following specification applies over,V5=5V,V12=12V,and Tj=0 to 125°C.Low duty
cycle pulse testing are used which keeps junction and case temperatures equal to the ambient temperature.
LDO Section
PARAMETER
Output Voltage
Line Regulation
Load Regulation (note 1)
Maximum Output Current
Thermal Regulation
Ripple Rejection
SYM TEST CONDITION
VOUT Io=0mA
Io=0mA, 4.75<V5<6V
0A<Io<7.5A
IMAX
dVo=0.995*VOUT
30 mS Pulse,V5=5V
f=120HZ ,Co=25uF Tan
Io=1A
MIN
TYP
3.400
MAX
0.2
0.5
7.5
UNITS
V
%
%
A
%/W
dB
0.01
70
0.02
MIN
1.237
1.225
-2
400
TYP
1.250
1.250
600
MAX
1.262
1.275
+2
800
UNITS
V
V
uA
nS
400
600
800
nS
Switching Controller Section
PARAMETER
F.B Voltage Initial Accuracy
F.B Voltage Total Variation
F.B Input Bias Current
Min On Time
Min Off Time
Vhyst pin output-HI
Vhyst pin output-LO
Supply Current
Maximum Duty Cycle
Minimum Duty Cycle
Gate Drive Rise/Fall Time
4-2
SYM
Vfb
Vfb
Ifb
TEST CONDITION
TJ =25°C
Includes Temp & line,4.75 to 5.25V
Vfb=1.25V
Vfb is sq wave with 300 ns on
time and 2 uS off time
Vfb is sq wave with 300 ns off
time and 2 uS on time
Isource=500uA,Vfb=1.5V
Isink=500uA,Vfb=1V
Icc
Vfb=1V
Dmax Vfb=1V
Dmin Vfb=1.5V
Vgate Load=IRL3303
11
1
10
100
0
70
V
V
mA
%
%
nS
Rev. 1.2
4/26/98
US2075
Note 1 : Low duty cycle pulse testing with Kelvin connections are required in order to maintain accurate data.
PIN DESCRIPTIONS
PIN #
3
PIN SYMBOL
Vfb
6
Vout
7
V5
4
Gnd
1
Drv
5
Vhyst
2
V12
PIN DESCRIPTION
A resistor divider from this pin to the output of the switching regulator and
ground sets the core supply voltage.
The output of the linear regulator. A minimum of a 10uF capacitor must be
connected from this pin to ground to insure stability. This voltage is set at 3.30V typ.
The input pin of the regulator. Typically a large storage capacitor is connected from
this pin to ground to insure that the input voltage does not sag below the minimum
drop out voltage during the load transient response. This pin must always be 1.3V
higher than Vout in order for the device to regulate properly.
This pin is connected to the IC substrate and must be connected to the lowest
potential in the system. It is also connected to the Tab of the package. A high
frequency capacitor must be connected from V12 to this pin to insure proper operation.
The PWM output of the switching controller. This pin is a totem pole drive that is
connected to the gate of the power MOSFET. A resistor may be placed from this
pin to the gate in order to reduce switching noise.
A resistor is connected from this pin to the Vfb pin to set the output ripple voltage.
See application note for more details.
This pin is connected to the 12V supply voltage A high frequency cap must be
connected from this pin to the GND pin of the IC.
BLOCK DIAGRAM
V12
2
Drv
1
Vhyst
5
Vfb
3
V5
7
Vout
6
UVLO
Vref
PWM Control
Gnd
4
1.25V
7.5A LDO
2075blk1-1.0
Figure 1 - Simplified block diagram of the US2075
Rev. 1.2
4/26/98
4-3
US2075
TYPICAL APPLICATION
L1
5V
C7
V5 7
Vo 6
Cache & Chip Set
Vhyst 5
U1
C5
Gnd 4
C8
JP7
R6A
Vfb 3
2
C4
R3
Drv 1
CPU I / O
3
L2
V12 2
1
Core Supply
Q2
C6
R8B
2050ta3d
R8C
12V
C1
R5
D2
R7A
JP2
Figure2- Typical application of US2075 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 P55,P54, AMD K5 & K6 as well as Cyrix M1 and
M2 applications. The jumper JP7 selects between single supply and dual supply processors.
Ref Desig
U1
Description
LDO/Switcher IC
JP2
JP3
JP4
JP5
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
C3
Qty
1
Q2
MOSFET
1
D2
Schottky Diode
1
L2
Inductor
1
L1
R3
R5
R8C
R8B
R7A
R7B
R7C
R7D
R7E
R6A
C8
C1
C7
C3
C4
C5
C6
HS1
HS2
HS3
Inductor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Resistor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Capacitor
Heat Sink
Heat Sink
Heat Sink
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4
1
1
1
R7B
JP3
R7C
JP4
R7D
JP5
R7E
Part #
US2075CT (TO220)
US2075CM (TO263) (note 1)
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 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
324 kohm,1%, SMT 0805 size
10pF,Ceramic, 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
For Schottky Diode , 577002
For US2075 , 507222 (I/O Load Current<5A)
576602 (I/O Load Current< 3.5A)
Output
Voltage
3.5
3.4
3.3
3.2
3.1
3.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
Manufacturer
Unisem
International
Rectifier
Motorola
Micro Metal
(core)
Panasonic
Sanyo
Panasonic
Sanyo
Aavid
Aavid
Aavid
Note 1: For the applications where it is desirable to eliminate the heat sink, the US2075CM 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.
4-4
Rev. 1.2
4/26/98