7.5A ULTRA DROPOUT POSITIVE ADJUSTABLE REGULATOR WITH SHUTDOWN INPUT

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

7.5A ULTRA DROPOUT POSITIVE ADJUSTABLE REGULATOR WITH SHUTDOWN INPUT

Datasheet Thumbnail

Top Searches for this datasheet

IRU1176
7.5A ULTRA DROPOUT POSITIVE ADJUSTABLE REGULATOR WITH SHUTDOWN INPUT
Guaranteed <TBDV Dropout 7.5A Fast Transient Response Voltage Reference Initial Accuracy Built-in Thermal Shutdown
DESCRIPTION
IRU1176 7.5A regulator with extremely dropout voltage using proprietary Bipolar process that achieves comparable equivalent resistance that discrete MOSFETs. IRU1176 also provides convenient shutdown that allows regulator shutdown reduce input current consumption. Unlike type regulators this device does have high quiescent current during start mode making ideal applications where there limited current capability such operation from standby supply computer power supply. application generation RDRAM memory that needs provide 2.5V from 3.3V input able operate from 5VSB well.
APPLICATIONS
3.3V 2.7V Intel I740 chipset
TYPICAL APPLICATION
3.3V
Vctrl
IRU1176
Vout Vsense
2.7V
1176app1-1.1
Enable
Typical application IRU1176
PACKAGE ORDER INFORMATION
(°C) 7-PIN PLASTIC TO-263 IRU1176CM 7-PIN PLASTIC ULTRA THIN-PAK IRU1176CP
Rev. 9/24/99
2-85
IRU1176
ABSOLUTE MAXIMUM RATINGS
Input Voltage (Vin) Control Input Voltage (Vctrl) Power Dissipation. Internally Limited Storage Temperature Range -65° 150° Operating Junction Temperature Range 150°
PACKAGE INFORMATION
7-PIN PLASTIC TO-263
FRONT VIEW
7-PIN PLASTIC ULTRA THIN-PAK
FRONT VIEW
Vctrl Vout Vsense
Vctrl Vout Vsense
JA=35°C/W 0.5" square
JA=35°C/W 0.5" square
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over, Cin=1µF, Cout =10µF, Tj=0 125°C. Typical values refer Tj=25°C. =Vsense. PARAMETER Reference Voltage Vref TEST CONDITION Vctrl=2.75V, Vin=2V, Io=10mA 1.243 Tj=25, Vadj=0V Vctrl=2.7to12V, Vin=2.05V 5.5V, 1.237 Io=10mA 7.5A, Vadj=0V Vctrl=2.5Vto7V, Vin=1.75Vto5.5V Io=10mA Vadj=0V Vctrl=2.75V, Vin=2.1V, Io=10mA 7.5A, Vadj=0V Vadj=0V conditions below. Vin=2.05V, Io=1.5A Vin=2.05V, Io=3A Vin=2.05V, Io=4A Vin=2.05V, Io=7.5A Vadj=0V conditions below. Vctrl=2.75V, Io=1.5A Vctrl=2.75V, Io=3A Vctrl=2.75V, Io=4A Vctrl=2.75V, Io=7.5A Vctrl=2.75V, Vin=2.05V dVo=100mV Vadj=0V Vctrl=5V, Vin=3.3V,Vadj=0V 30mS Pulse Vctrl=5V, Vin=5V,Io=4A, Vadj=0V Tj=25, Vripple=1Vpp 120Hz Vctrl=5V, S.D=0V 1.250 1.250 1.257 1.263 UNITS
Line Regulation Load Regulation (note Dropout Voltage (note ctrl Vout
0.95 1.00 1.05 1.15 0.075 0.150 0.200 0.375 0.01
Vctrl
Dropout Voltage (note Vout
Current Limit Minimum Load Current (note Thermal Regulation Ripple Rejection Threshold Voltage Input Current
0.02
Rev. 9/24/99
Vctrl
2-86
IRU1176
ELECTRICAL SPECIFICATIONS
PARAMETER
Control Current
TEST CONDITION
Vadj=0V below conditions. Vctrl=2.75V,Vin=2.05V,Io=1.5A Vctrl=2.75V,Vin=2.05V,Io=3A Vctrl=2.75V,Vin=2.05V,Io=4A Vctrl=2.75V,Vin=2.05V,Io=7.5A
UNITS
Adjust Current
Iadj
Vctrl=2.75V,Vin=2.05V,Vadj=0V,
Note duty cycle pulse testing with Kelvin connections required order maintain accurate data. Note Dropout voltage defined minimum differential between required maintain regulation Vout measured when output voltage drops below nominal value.
Note Minimum load current defined minimum current required output order output voltage maintain regulation. Typically resistor dividers selected such that automatically maintains this current.
DESCRIPTIONS
SYMBOL DESCRIPTION Vsense This positive side reference which allows remote load sensing achieve excellent load regulation. When this pulled lower than 1.4V with respect Vctrl device shutdown. enable operation leave this open. Internal device, there pull resistor. resistor divider from this Vout ground sets output voltage. output regulator. minimum 10µF capacitor must connected from this ground insure stability. This supply internal control circuitry well base drive pass transistor. This must always higher than Vout order device regulate. (see specifications) input regulator. Typically large storage capacitor connected from this ground insure that input voltage does below minimum drop voltage during load transient response. This must always higher than Vout order device regulate. (see specifications)
Vout
Vctrl
Rev. 9/24/99
2-87
IRU1176
BLOCK DIAGRAM
Vout
Vctrl
1504
Vsense
1.25V CURRENT LIMIT
THERMAL SHUTDOWN
1176blk1-1.0
OUTPUT SHUTDOWN
Figure Simplified block diagram IRU1176
APPLICATION INFORMATION
Introduction IRU1176 adjustable regulator five-terminal device designed specifically provide extremely dropout voltages comparable type without disadvantage extra power dissipation base current associated with regulators. This done bringing control regulator that provides base current power connecting voltage that grater than voltage present pin. This flexibility makes IRU1176 ideal applications where dual inputs available such computer motherboard with style power supply that provides 3.3V board. such application graphic chip sets that require anywhere from 2.4V 2.7V supply such Intel I740 chipset. IRU1176 easily programmed with addition external resistors voltages within range 1.25 Another major requirement these graphic chips need switch load current from zero several amps tens nanoseconds processor pins, which translates approximately 500nS current step regulator. addition, output voltage tolerances also extremely tight they include transient response part specification.
IRU1176 specifically designed meet fast current transient needs well providing accurate initial voltage, reducing overall system cost with need fewer number output capacitors. Another feature device true remote sensing capability which allows accurate voltage setting load rather than device. Output Voltage Setting IRU1176 programmed voltages range 1.25V 5.5V with addition external resistors according following formula: VOUT VREF IADJ Where: VREF=1.25V Typically IADJ=50µA Typically shown Figure
Vout
Vout
IRU1176 Vctrl
Vctrl Open IAdj 50uA
1176app2-1.0
Vsense
Vref
Figure Typical application IRU1176 programming output voltage
2-88
Rev. 9/24/99
IRU1176
IRU1176 keeps constant 1.25V between Vsense Vadj pin. placing resistor across these pins connecting Vsense Vout together, constant current flows through adding Iadj current into resistor producing voltage equal (1.25/R1)*R2 Iadj*R2.This voltage then added 1.25V output voltage. This summarized above equation. Since minimum load current requirement IRU1176 10mA, typically selected resistor that automatically satisfies this condition. Notice that since Iadj typically range 50µA only adds small error output voltage should considered when very precise output voltage setting required. Load Regulation Since IRU1176 separate pins output sense sense), ideal providing true remote sensing output voltage load. This means that voltage drops parasitic resistance such traces between regulator load compensated using remote sensing. Figure shows typical application IRU1176 with remote sensing.
Vout
most applications minimum 100µF aluminum electrolytic capacitor such Sanyo, MVGX series, Panasonic series well Nichicon series insures both stability good transient response. Shutdown Operation IRU1176 disabled pulling using open collector device such cost 2N3904 general purpose transistor shown application circuit. current sink equal Isink=(V ctrl-1.4)/R where, R=50 typ. Thermal Design IRU1176 incorporates internal thermal shutdown that protects device when junction temperature exceeds allowable maximum junction temperature. Although this device operate with junction temperatures range 150°C, recommended that selected heat sink chosen such that during maximum continuous load operation junction temperature kept below this number. example below shows steps selecting proper surface mount package. Assuming, following conditions: Vout =2.7V Vin=3.3V Vctrl=5V Iout Calculate maximum power dissipation using following equation: Pd=Iout in-V (Iout /60)*(V ctrl Vout Pd=2*(3.3-2.7) (2/60)*(5-2.7)=1.28 Using table below select proper package amount copper board needed. Copper JA(°C/W) Area 1.4"X1.4" 1.0"X1.0" 0.7"X0.7" Size (Ta=25°C) 4.4W 3.7W 3.1W 2.4W (Ta=45°C) 3.6W 3.0W 2.6W 2.0W
IRU1176 Vctrl
Vctrl Vsense
1176app3-1.0
Figure Schematic showing connection best load regulation Stability IRU1176 requires output capacitor part frequency compensation order make regulator stable. Typical designs microprocessor applications standard electrolytic capacitors with typical range 100m output capacitance 1000µF. Fortunately capacitance increases, decreases resulting fixed time constant. IRU1176 takes advantage this phenomena making overall regulator loop stable.
Note: Above table based maximum junction temperature 135°C. shown above table, packages will job. lower cost applications Ultra ThinPak package recommended.
Rev. 9/24/99
2-89
IRU1176
Notes
2-90
Rev. 9/24/99

7.5A ULTRA DROPOUT POSITIVE ADJUSTABLE REGULATOR WITH SHUTDOWN INPUT

Top Searches for this datasheet

Other recent searches