UNISEM US1061CT, US1061CP, US1061CM Datasheet
US1261
3-1
Rev. 1.7
3/22/99
PACKAGE ORDER INFORMATIONPACKAGE ORDER INFORMATION
TYPICAL APPLICATIONTYPICAL APPLICATION
FEATURESFEATURES
Guaranteed to provide 1.5V and 2.5V Supplies with 3.1V input.
Fast Transient Response
1% Voltage Reference Initial Accuracy
Built in Thermal Shutdown
APPLICATIONSAPPLICATIONS
Pentium II Processor Applications
DESCRIPTIONDESCRIPTION
The US1261 product using a proprietary process combines a dual low dropout regulators with fixed outputs of
1.5V and 2.5V in a single package with the 1.5V output having a minimum of 6A and the 2.5V having a 1A
output current capability. This product is specifically designed to provide well regulated supplies from 3.3V to
generate 1.5V for GTL+ termination resistor supply
and 2.5V clock supply for the new generation of
the Pentium II processor applications.
DUAL 6A AND 1A LOW DROPOUT
POSITIVE FIXED OUTPUT REGULATOR
Typical application of US1261 in a Pentium II processor application
3.3V
2.5V / 1A
US1261
1.5V / 6A
C1
C3
C4
1261app1-1.3
5V
C2
1
2
3
4
5
Vctrl
Vout2
Gnd
Vin
Vout1
R1
Tj (°C) 5 PIN PLASTIC 5 PIN PLASTIC 5 PIN PLASTIC
TO220(T) TO263(M) POWER FLEX(P)
0 TO 150 US1261CT US1261CM US1261CP
US1261
3-2
Rev. 1.7
3/22/99
Unless otherwise specified ,these specifications apply over ,Cin=1 uF,Cout=100uF,and Tj=0 to 150°C.Typical
values refer to Tj=25°C. Ifl=6A for output #2 & 1A for output #1.Vctrl=5V,Vin=3.3V.
PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS
Vctrl Input Voltage 3.0 V
Output Voltage #2 Vo2 Io=10mA, Tj=25°C 1.485 1.500 1.515 V
Io=10mA 1.470 1.500 1.530
Output Voltage #1 Vo1 Io=10mA, Tj=25°C 2.462 2.500 2.537 V
Io=10mA 2.425 2.500 2.575
Line Regulation Io=10mA, 3.1V<Vin<3.6V 0.2 %
Load Regulation (note 1) 10mA<Io<Ifl 0.4 %
Dropout Voltage (output #2) Note 2,
Io=6A, Vctrl=4.75V 1.3 V
Dropout Voltage (output #1) Note 2,
Io=1A, Vctrl=4.75V 0.4 0.6 V
Current Limit (output #2) dVo=100mV 6.1 A
Current Limit (output #1) dVo=100mV 1.1 A
Minimum Load Current 5 10 mA
(note 3)
Thermal Regulation 30 mS PULSE,Io=Ifl 0.01 0.02 %/W
Ripple Rejection f=120HZ ,Co=25uF Tan
Io=0.5*Ifl 70 dB
Temperature Stability Io=10mA 0.5 %
Long Term Stability Tj=125°C,1000 Hrs 0.3 %
RMS Output Noise 10hz<f<10khz 0.003 %Vo
Note 3 : Minimum load current is defined as the minimum current required at the output in order for the output voltage to maintain regulation. Typically the resistor
dividers are selected such that it automatically maintains this current.
ABSOLUTE MAXIMUM RATINGSABSOLUTE MAXIMUM RATINGS
Input Voltage (Vin) ............................................................. 10V
Power Dissipation ............................................ Internally Limited
Storage Temperature Range ................................ -65°C TO 150°C
Operating Junction Temperature Range ...................... 0°C TO 150°C
PACKAGE INFORMATIONPACKAGE INFORMATION
7 PIN PLASTIC TO220 7 PIN PLASTIC TO263 7 PIN POWER FLEX (P)
θJT =2.7°C/W θJA =60°C/W θJA =30°C/W for 1"sq pad θJA =30°C/W for 1"sq pad
ELECTRICAL SPECIFICATIONSELECTRICAL SPECIFICATIONS
Note 1 : Low duty cycle pulse testing with Kelvin connections are required in order to maintain accurate data.
Note 2 : Drop-out voltage is defined as the minimum
differential voltage between Vin and Vout required to maintain regulation at Vout. It is measured when the output
voltage drops 1% below its nominal value.
FRONT VIEW
1
2
3
4
5
Vctrl
Gnd
Vout2
Vin
Vout1
Vctrl
Gnd
Vout2
Vin
Vout1
FRONT VIEW
1
2
3
4
5
FRONT VIEW
1
2
3
4
5
Vctrl
Gnd
Vout2
Vin
Vout1
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