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(R)
SPX1581
5A Ultra Low Dropout Voltage Regulator
Fast Response, Adjustable & Fixed
FEATURES
Low Dropout Voltage 500mV at 5A Full Load Current Adjustable Ouput Down to 1.2V from ATX Power Supply Fixed Output Voltages of 3.3V, 2.8V and 2.5V Extremely Tight Load and Line Regulation Standard 5-Terminal Low Cost TO-220 and TO-263
ADJ OR FIXED SENSE VCNTRL VOUT VIN
SPX1581
5 Pin TO-263
SPX1581
5 Pin TO-220
12345
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APPLICATIONS
3.3V to 2.8V ATX Power Supplies 3.3V to 2.9V for Portable PENTIUMTM Processor 5V to 3.5V VRE Supply High efficiency "Green" Computer Systems
ADJ OR FIXED
SENSE
Now Available in Lead Free Packaging
DESCRIPTION
The SPX1581 is a 5A Low Dropout Regulator with extremely low dropout voltage. The adjustable version requires only two external resistors to set the output voltage. The fixed version has a preset output of 3.3V, 2.8V or 2.5V and does not require any external resistors. The SPX1581 features a low dropout of 400mV(Typ.) and offers fast transient response. This device is suitable for Pentium applications requiring 2.8V, 2.5V from 3.3V ATX power supplies, where a low current input voltage 1V greater than the output voltage is needed. With an external sense pin the load regulation is less than 1mV. This device is an excellent choice for the use of powering low voltage microprocessors that require a lower dropout, fast transient response to regulate from 3.3V and 5V supplies. The SPX1581 is also an excellent choice as a post regulator for switching supplies applications. The SPX1581 offers protection against over-current faults, reversed input polarity, over temperature operation and positive and negative transient voltage. The SPX1581 is offered in a 5 pin TO-220 and TO-263 compatible with industry standard 5-terminal regulators. For 7A, 3A and 1.5A ultra low dropout versions refer to SPX1580, SPX1582 and SPX1583 data sheets respectively.
TYPICAL APPLICATIONS CIRCUIT
3.3V VIN 5V VCTRL VIN C1 330F VCTRL 5 SPX1581 4 2 ADJ C2 10F C3 .033F R2 124 1 SENSE R1 124 C4 2x330F 3 VOUT 2.5V VOUT
3.3V VIN 5V VCTRL VIN C1 330F VCTRL 5 SPX1581 4 2 GND C2 10F 1 SENSE 3 VOUT 2.5V VOUT
VCNTRL
VOUT
VIN
C4 2x330F
(1) VCTRL needed when VIN < 5V. (2) VOUT = VREF (1+R2/R1)+IADJ R2. (3) VREF is measured across adjust to sense.
(1) VCTRL needed when VIN < 5V.
Adjustable Regulator
Typical Fixed Regulator
Date 5/25/04
SPX1581 5A Ultra Low Dropout Voltage Regulator
(c)Copyright 2004 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
Power Dissipation ..................................... Internally Limited Lead Temp. (Soldering, 10 Seconds) ......................... 300C Storage Temperature Range ..................... -65C to +150C Operating Junction Temperature Range SPX1581 Control Section ............................. 0C to +125C SPX1581 Power Transistor .......................... 0C to +150C Input Supply Voltage ..................................................... 6V VCTRL Input Voltage ....................................................... 13V
ELECTRICAL CHARACTERISTICS
Electrical characteristics at VOUT = VSENSE, VADJ = 0V, TA=25C, CCTL = CPWR = COUT = 33F tantalum cap otherwise specified. The denotes the specifications which apply over full temperature range -40C to +85C, unless otherwise specified. PARAMETER 2.5V Version Output Voltage 2.8V Version Output Voltage 3.3V Version Output Voltage All Voltage Options Reference Voltage Line Regulation Load Regulation (Note 1) Dropout Voltage Min. VCTRL (Note 2) (VCTRL - VOUT) Dropout Voltage Min. VIN (Note 2) (VIN - VOUT) Current Limit Minimum Load Current Thermal Regulation Ripple Rejection Control Pin Current Adjustble Pin Current Thermal Resistance TO-220-5 Thermal Resistance TO-263-5 1.0 1.0 1.10 0.40 5.1 5 0.002 80 60 50 120 3 50 3 60 10 0.02 3.0 5.0 1.25 0.50 MIN 2.450 2.400 2.744 2.688 3.234 3.168 1.238 TYP 2.5 MAX 2.550 2.600 2.856 2.912 3.366 3.432 1.263 UNITS CONDITIONS V VCTRL = 6.0V to 12V, VIN = 3.0V to 5.0V, IO =10mA IO = 10mA to 5A VCTRL = 6.3V to 12V, VIN =3.3V to 12V, IO=10mA IO = 10mA to 5A VCTRL = 6.3V to 12V, VIN = 3.3V + 0.8V, IO=10mA IO = 10mA to 5A VCTRL = 2.75V, VIN = 2.00V, IO = 10mA VCTRL=2.7V to 12V,VIN = 2.05V to 5.5V,IO=10mA to 5A VCTRL = 2.5V to 12V, VIN = 1.75V to 5.5V, IO=10mA VADJ=0V VCTRL = 2.75V, VIN = 2.1V, IO=10mA to 5A, VADJ = 0V VADJ = 0V VIN = 2.05V, IO = 1A VADJ = 0V VIN = 2.75V, IO = 5A VCTRL = 2.75V, VIN = 2.05V, VOUT = 100mV, VADJ = 0V VCTRL = 5V, VIN=3.3V, VADJ=0V 30ms Pulse VCTRL = 3.75V, VIN = 3.75V, IO = 2.5A, VADJ=0V TJ=25, VRIPPLE=1Vpp at 120Hz VADJ = 0V VCTRL = 2.75V, VIN = 2.05V, IO = 5A VCTRL = 2.75V, VIN = 2.05V, VADJ=0V, IO = 10mA Junction to Case (JC) Junction to Ambient (JA) Junction to Case (JC) Junction to Ambient (JA)
2.8
V
3.3 3.3 1.25
V
V mV mV V V A mA %/W dB mA A C/W C/W C/W C/W
60
120
Note 1: Low duty cycle pulse testing with Kelvin connections is required to order to maintain accurate data. Note 2: Dropout voltage is defined as the minimum differential between VIN and VOUT or VCTRL and VOUT required to maintain regulation at VOUT 95% Nominal VOUT. Note 3: VREF is measured across Adjust pin to Sense pin.
Date 5/25/04
SPX1581 5A Ultra Low Dropout Voltage Regulator
(c)Copyright 2004 Sipex Corporation
2
PIN DESCRIPTION
PIN NUMBER 1 2 PIN NAME SENSE ADJ DESCRIPTION Allows Kelvin sense of VOUT at the load. (Positive side of the reference voltage of the device). Negative side of the reference voltage for the device. Adding a small bypass capacitor from the ADJ pin to ground will improve the transient response. Power output of the device. Supply pin for the control circuitry of the device. The current flow into this pin will be about 1% of the output current. VCTRL must be between 1.0V and 1.3V greater than the output voltage for the device to regulate. Output load current is supplied through this pin. VIN must be between 0.1V and 0.8V greater than the output voltage for this device to regulate.
3 4
VOUT VCTRL
5
VIN
FUNCTIONAL DIAGRAM
(4) VCTRL VIN (5)
S.O.A
CURRENT LIMIT AMPLIFIER
LIMIT
SENSE
VOUT (3)
THERMAL OVERLOAD
SENSE (1)
VOLTAGE REGULATION AMPLIFIER
VREF
ADJ (2)
APPLICATION NOTES The SPX1581 is designed as a high performance and low cost solution for application requiring a lower dropout than traditional NPN regulators. The SPX1581 uses a separate input voltage VCTRL ( VCTRL VOUT + 1.3V) to minimize the dropout voltage. This allows the 2.5V power for the load to come from a 3.3V system supply. As added benefit this will reduce the heat dissipation*, and lower heatsink and cooling fan cost.
* The reduction of heat dissipation is a result of the increase of the regulator efficiency (efficiency = VOUT/VIN).
Date 5/25/04 SPX1581 5A Ultra Low Dropout Voltage Regulator (c)Copyright 2004 Sipex Corporation
A typical application would use 5V for VIN and 3.3V for VCTRL from a motherboard power supply to provide a nominal 2.5V output. Using the sense pin allows Kelvin measure the output, reducing resistance-associated errors. The SPX1581 can power the 2.5V core voltage for microprocessors such as a PentiumTM, P55CTM, AMD5k86TM and K6TM and the IBM PowerPCTM 603EV and 604EV processors.
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APPLICATION NOTES: Continued Adjustable Regulator Design 1.25V reference voltage is being developed between the SENSE pin and the ADJ pin of the SPX1581. Adding two external resistors (see fig 1.) will allow setting the output voltage from 1.25V to 6V. R1 is chosen so that this current is specified minimum load current of 10mA. R2 is given by the formula: VOUT = VREF (1+ R2/R1) + IADJ (R2). The current flowing from the ADJ pin is typicaly 50A. This ADJ pin contributes to the final VOUT but is usually neglected. Connecting the sense pin to the top of the resistor divider will improve load regualtion. Lowering Noise Using the SENSE pin to Kelvin the load will increase accuracy of the output voltage during load regulation. For the fixed voltage device, adding a capacitor at the GND pin will improve transient response. This capacitor is chosen in the range of 1F to 0.1F and will depend on the amount of output capacitance in the system.
Date 5/25/04
SPX1581 5A Ultra Low Dropout Voltage Regulator
(c)Copyright 2004 Sipex Corporation
4
PACKAGE: 5 Pin TO-220
E E/2
A B
A
SEATING PLANE
Q H1
oP
F
D D1 L1
D CHAMFER OPTIONAL
CC
D
D L
e e1
b
C1 J1
A
5 PIN TO-220
Dimensions in (inches)
MIN NOM MAX
A b C1 D E e e1 F H1 J1 L L1 P Q U V
.160 .015 .014 .560 .385 .385 .062 .045 .234 .090 .540
-
.190 .040 .022 .590 .415 .415 .072 .055 .258 .115 .560 .250 .156 .113 -
.146 .103 -
.30 .24
5 PIN TO-220
Date 5/25/04
SPX1581 5A Ultra Low Dropout Voltage Regulator
(c)Copyright 2004 Sipex Corporation
5
PACKAGE: 5 Pin TO-263
SEATING PLANE
(DATUM A)
A C2
H
E 1 2 3 4 5 L2
(E)
c
E
L1
D1
5X b 4X e
E1
5 PIN TO-263 JEDEC TO-263 (BB) Variation A A1 b c c2 D1 E E1 e H L L1 L2 L3
Dimensions in (mm) MIN .160 0 .020 .015 .045 .270 .380 .245 NOM MAX .067 BSC .575 .070 .625 .110 .066 .070
c
.190 .010 .039 .029 .023 .420 (b)
0-8 L3
L
WITH PLATING
.010 BSC
BASE METAL CONTACT AREA
5 PIN TO-263
Date 5/25/04 SPX1581 5A Ultra Low Dropout Voltage Regulator (c)Copyright 2004 Sipex Corporation
6
ORDERING INFORMATION Part Number Accuracy Output Voltage Packages
SPX1581U5 ............................... SPX1581U5-2.5 ......................... SPX1581U5-2.8 ......................... SPX1581U5-3.3 ......................... SPX1581T5 ................................ SPX1581T5/TR .......................... SPX1581T5-2.5 .......................... SPX1581T5-2.5/TR .................... SPX1581T5-2.8 .......................... SPX1581T5-2.8/TR .................... SPX1581T5-3.3 .......................... SPX1581T5-3.3/TR .................... 2.0% ............................. Adj .......................... 5-Pin TO-220 2.0% ............................ 2.5V ........................ 5-Pin TO-220 2.0% ............................ 2.8V ........................ 5-Pin TO-220 2.0% ............................ 3.3V ........................ 5-Pin TO-220 2.0% ............................. Adj .......................... 5-Pin TO-263 2.0% ............................. Adj .......................... 5-Pin TO-263 2.0% ............................ 2.5V ........................ 5-Pin TO-263 2.0% ............................ 2.5V ........................ 5-Pin TO-263 2.0% ............................ 2.8V ........................ 5-Pin TO-263 2.0% ............................ 2.8V ........................ 5-Pin TO-263 2.0% ............................ 3.3V ........................ 5-Pin TO-263 2.0% ............................ 3.3V ........................ 5-Pin TO-263
Available in lead free packaging. To order add "-L" suffix to part number. Example: SPX1581T5-3.3/TR = standard; SPX1581T5-L-3.3/TR = lead free /TR = Tape and Reel Pack quantity is 500 for TO-263.
Corporation
ANALOG EXCELLENCE
Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Date 5/25/04
SPX1581 5A Ultra Low Dropout Voltage Regulator
(c)Copyright 2004 Sipex Corporation
7

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