UNISEM US2076CT, US2076CM Datasheet
ADJUSTABLE LOW DROPOUT REGULATOR COMBO
FEATURESFEATURES
The US2076 eliminates the need for a
seperate switching controller IC
Minimum part count allows lower system cost
Adjustable 7.5A LDO on board
1.1V Dropout at 7.5A
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
APPLICATIONSAPPLICATIONS
Dual supply low voltage processor applications,
such as: P55C,CYRIX M2, POWER PC and
AMD K6
US2076
PWM SWITCHER CONTROLLER & 7.5A
PATENT PENDING
PRELIMINARY DATASHEET
DESCRIPTIONDESCRIPTION
The US2076 is a dual function IC combining a
switching controller and a 7.5A adjustable 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 M2processors. Typically in these applications
a dual supply regulator converts 5V to 3.3V for I/O supply and a jumper programmable supply of 1.25V to 3.5V
for CORE supply.The linear regulator portion in the
US2076 is an adjustable one that can be programmed
to 3.30V output and has a minimum of 7.5A current capability designed to provide ample current for most applications. The US2076 uses an internal regulator generated from the 12V supply to power the switching controller as well as the 12V supply to drive the power
MOSFET, allowing a low cost N channel MOSFET
switch to be used. The IC also includes an error comparator for fast 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 APPLICATIONTYPICAL APPLICATION
L1
I / O
C6
CPU
Vcc2 Det
Core
C7
2076app1-1.2
US2076
5V
12V
Vin
Vout
Vfb2
Gnd
Vfb1
V12
Drv
C1
7
6
5
4
3
2
R1
1
C3
C2
Q2
D1
R6
R7
D2
5V
R8
L2
R4
R5
Typical application of US2076 in a flexible motherboard 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 INFORMATIONPACKAGE ORDER INFORMATION
Tj (°C) 7 PIN PLASTIC 7 PIN PLASTIC
TO220 (T) TO263 (M)
0 TO 125 US2076CT US2076CM
Rev. 1.3
4/26/98
4-1
US2076
ABSOLUTE MAXIMUM RATINGSABSOLUTE MAXIMUM RATINGS
12V Supply Voltage ............................................................. 14V
Vin 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 ............................... 0 TO 150°C
PACKAGE INFORMATIONPACKAGE INFORMATION
7 PIN PLASTIC TO220 (T) 7 PIN PLASTIC TO263 (M)
FRONT VIEW
7
6
5
4
3
2
1
Vin
Vfb2
Vfb1
Drv
Vout
Gnd
V12
FRONT VIEW
7
Vin
6
Vout
5
Vfb2
4
Gnd
3
Vfb1
2
V12
1
Drv
θJT=2.7°C/W θJA=60°C/W θJA=35°C/W for 1" Square pad
ELECTRICAL SPECIFICATIONSELECTRICAL SPECIFICATIONS
Unless otherwise specified the following specification applies over,Vin=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 SYM TEST CONDITION MIN TYP MAX UNITS
F.B Voltage Initial Accuracy Vfb2 Tj=25°C 1.237 1.250 1.262 V
F.B Voltage Total Variation Vfb2 1.225 1.250 1.275 V
F.B Input Bias Current Ifb2 Vfb2=1.25V -1 +1 uA
Dropout Voltage (note 2) Vout=1.25V, Io=7.5A 1.1 V
Line Regulation Vout=1.25V,Io=10mA, 3<Vin<6V 0.2 %
Load Regulation (note 1) Vout=1.25V, 10mA<Io<7.5A 0.5 %
Thermal Regulation 30 mS Pulse 0.01 %/W
Minimum Load Current (note 3) 10 mA
Ripple Rejection f=120HZ ,Co=25uF Tan,Io=1A 70 dB
V12 Supply Current Icc2 Vfb2=1V, Vfb1=1.5V, Io=7.5A 75 mA
Switching Controller Section
PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS
F.B Voltage Initial Accuracy Vfb1 Tj=25°C 1.237 1.250 1.262 V
F.B Voltage Total Variation Vfb1 1.225 1.250 1.275 V
F.B Input Bias Current Ifb1 Vfb1=1.25V -1 +1 uA
Min On Time Vfb1 is sq wave with 300 ns on 800 nS
time and 2 uS off time
Min Off Time Vfb1 is sq wave with 300 ns off 800 nS
time and 2 uS on time
V12 Supply Current Icc1 Vfb1=1V, Vfb2=1.5V 10 mA
Maximum Duty Cycle Dmax Vfb1=1V 100 %
Minimum Duty Cycle Dmin Vfb1=1.5V 0 %
Gate Drive Rise/Fall Time Vgate Load=IRL3303 70 nS
F.B Hysterises 12 mV
4-2
Rev. 1.3
4/26/98
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