UNISEM US1150CS, US1150CP, US1150CM Datasheet
US1150
4A ULTRA LOW DROPOUT POSITIVE
ADJUSTABLE REGULATOR
PRELIMINARY DATASHEET
FEATURESFEATURES
0.7V Dropout at 4A
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
Vin
DESCRIPTIONDESCRIPTION
The US1150 product is a 4A regulator with extremely
low dropout voltage using a proprietary Bipolar process that achieves comparable equivalent on resistance to that of discrete MOSFETs. This product is
specifically designed to provide well regulated supply for
applications requiring 2.8V or lower voltages from
3.3V ATX power supplies where high efficiency of
a switcher can be achieved without the cost and
complexity associated with switching regulators.
One such application is the new graphic chip sets that
require anywhere from 2.4V to 2.7V supply such as the
Intel I740 chip set.
C1
5
Vctrl
4
Vout
Adj
3
R1
2
1
C2
R2
C3
US1150
Vsense
1150app1-1.0
5V
Typical application of US1150 in a 3.3V to 2.7V for I740 chip.
PACKAGE ORDER INFORMATIONPACKAGE ORDER INFORMATION
Tj (°C) 5 PIN PLASTIC 5 PIN PLASTIC 8 PIN PLASTIC
TO263 (M) POWER FLEX (P) SOIC (S)
0 TO 125 US1150CM US1150CP US1150CS
2.7V
Rev. 1.2
10/28/99
2-1
US1150
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
8 PIN PLASTIC SOIC ( S ) 5 PIN PLASTIC TO263 ( M ) 5 PIN PLASTIC POWER FLEX (P)
FRONT VIEW
5
Vin
4
Vctrl
3
Vout
2
Adj
1
Vsense
Vctrl
Vin
Adj
TOP VIEW
1
2
3
4
8
Vout
7
Vout
6
Vout
5
VoutVsense
θJA=55°C/W for 1" Sq pad area θJA=35°C/W for 0.5" square pad θJA=35°C/W for 0.5" square pad
FRONT VIEW
5
Vin
4
Vctrl
3
Vout
2
Adj
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 4A,Vadj=0V
Line Regulation Vctrl=2.5Vto7V,Vin=1.75Vto5.5V
,Io=10mA ,Vadj=0V 3 mV
Load Regulation (note 1) Vctrl=2.75V,Vin=2.1V,Io=10mA
to 4A,Vadj=0V 5 mV
Dropout Voltage (note 2) Vadj=0V for all conditions below.
(Vctrl - Vout) Vin=2.05V,Io=1.5A 1.15 V
Vin=2.05V,Io=3A 1.18
Vin=2.05V,Io=4A 1.10 1.25
Dropout Voltage (note 2) Vadj=0V for all conditions below.
(Vin - Vout) Vctrl=2.75V,Io=1.5A 0.26 0.38 V
Vctrl=2.75V,Io=3A 0.50 0.60
Vctrl=2.75V,Io=4A 0.70 0.85
Current Limit Vctrl=2.75V,Vin=2.05V,
dVo=100mV Vadj=0V 4.2 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
2-2
Rev. 1.2
10/28/99
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