UNISEM US1176CP, US1176CM Datasheet
US1176
7.5A ULTRA LOW DROPOUT POSITIVE
ADJUSTABLE REGULATOR WITH SHUTDOWN INPUT
PRELIMINARY DATASHEET
FEATURESFEATURES
Guaranteed <TBDV Dropout at 7.5A
Fast Transient Response
1% Voltage Reference Initial Accuracy
Built-in Thermal Shutdown
APPLICATIONSAPPLICATIONS
3.3V to 2.7V Intel I740 chip set.
TYPICAL APPLICATIONTYPICAL APPLICATION
3.3V
US1176
Vin
Vin
Vctrl
Vout
Adj
SD
Vsense
C1
DESCRIPTIONDESCRIPTION
The US1176 product is a 7.5A regulator with extremely
low dropout voltage using a proprietary Bipolar process that achieves comparable equivalent on resistance to that of discrete MOSFETs. The US1176
also provides a convenient Shutdown pin that allows the
regulator to be shutdown and reduce the input current
consumption. Unlike the PNP type regulators this device does not have high quiecent current during the start
up mode making it ideal for applications where there is
limited current capability such operation from the 5V
Standby supply of the computer power supply.One application is the new generation of the RDRAM memory
that needs to provide 2.5V from 3.3V input and be able
to operate from 5VSB as well.
7
6
5
4
3
2
1
R1
R2
2.7V
C3
1176app1-1.1
5V
Typical application of US1176 .
C2
Q1
SD Enable
PACKAGE ORDER INFORMATIONPACKAGE ORDER INFORMATION
Tj (°C) 7 PIN PLASTIC 7 PIN PLASTIC
TO263 (M) POWER FLEX (P)
0 TO 125 US1176CM US1176CP
Rev. 1.1
9/24/99
2-1
US1176
ABSOLUTE MAXIMUM RATINGSABSOLUTE MAXIMUM RATINGS
Input Voltage (Vin) ........................................................... 7V
Control Input Voltage (Vctrl) .................................................. 14V
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 TO263 ( M ) 7 PIN PLASTIC POWER FLEX (P)
FRONT VIEW
7
Vin
6
Vin
5
Vctrl
4
Vout
3
Adj
2
SD
1
Vsense
θJA=35°C/W for 0.5" square pad θJA=35°C/W for 0.5" square pad
FRONT VIEW
7
Vin
6
Vin
5
Vctrl
4
Vout
3
Adj
2
SD
1
Vsense
ELECTRICAL SPECIFICATIONSELECTRICAL SPECIFICATIONS
Unless otherwise specified ,these specifications apply over ,Cin=1uF,Cout=10uF, and Tj=0 to 125°C.Typical
values refer to Tj=25°C. Vout=Vsense.
PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS
Reference Voltage Vref Vctrl=2.75V,Vin=2V,Io=10mA 1.243 1.250 1.257 V
Tj=25,Vadj=0V
Vctrl=2.7to12V,Vin=2.05V to 5.5V, 1.237 1.250 1.263
Io=10mA to 7.5A,Vadj=0V
Line Regulation Vctrl=2.5Vto7V,Vin=1.75Vto5.5V
,Io=10mA ,Vadj=0V 0.5 mV
Load Regulation (note 1) Vctrl=2.75V,Vin=2.1V,Io=10mA
to 7.5A,Vadj=0V 5 mV
Dropout Voltage (note 2) Vadj=0V for all conditions below.
(Vctrl - Vout) Vin=2.05V,Io=1.5A 0.95 V
Vin=2.05V,Io=3A 1.00
Vin=2.05V,Io=4A 1.05
Vin=2.05V,Io=7.5A 1.15
Dropout Voltage (note 2) Vadj=0V for all conditions below.
(Vin - Vout) Vctrl=2.75V,Io=1.5A 0.075 V
Vctrl=2.75V,Io=3A 0.150
Vctrl=2.75V,Io=4A 0.200
Vctrl=2.75V,Io=7.5A 0.375
Current Limit Vctrl=2.75V,Vin=2.05V,
dVo=100mV Vadj=0V 7.7 9 A
Minimum Load Current (note 3) Vctrl=5V,Vin=3.3V,Vadj=0V, 5 10 mA
Thermal Regulation 30 mS Pulse 0.01 0.02 %/W
Ripple Rejection Vctrl=5V,Vin=5V,Io=4A,Vadj=0V 60 70 dB
Tj=25,Vripple=1Vpp at 120Hz
S.D Threshold Voltage Vctrl - 1.4 Vctrl - 2.2 V
S.D Input Current Vctrl=5V, S.D=0V 94 130 uA
2-2
Rev. 1.1
9/24/99
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