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Bay Linear
Inspire the Linear Power
4.0A Low Dropout Voltage Regulator
Adjustable & Fix Output
B1587
Description
The Bay Linear B1587 is Monolithic low power 4.0A Adjustable and fixed NPN voltage regulator that are easy to use with minimum external components. It is suitable for applications requiring a well-regulated positive output voltage with low input-output differential voltage requirements and output voltage 1.5V, 2.5V, 3.0V, 3.3V, or 5V. The B1587 Outstanding features include full power usage up to 4.0Amp of load current internal current limiting and thermal shutdown. Other fixed versions are also available consult with factory. The B1587 is offer in a new LPDD (Low Profile TO263) package from 4.47 mm (DD) thickness down to only 1.27 mm (LPDD) total thickness. The B1587 is offered in a 3-pin TO-220, TO-263 & TO-252 packages compatible with other 3 terminal regulators. For 5A Low dropout Regulator refer to the B1585 data sheet.
Features
* * * * * * Adjustable Output Down to 1.2V Fixed Output Voltages 2.5V, 3.0V 3.3V, and 5.0V Output Current of 4.0A Low Dropout Voltage 1.1V Typ. Current & Thermal Limiting Standard 3-Terminal Low Cost TO-220, D2, D Packages Similar to industry Standard LT1085/LT1587/LT1585
*
Applications
* * * * * * 3.3V to 2.5V for Pentium Processor SMPS Post Regulator High Efficiency "Green" Computer Systems High Efficiency Linear Power Supplies 5V to 3.XXV for Pentium Processor Battery Charger
Pin Connection
Ordering Information
Devices
B1587T B1587S B1587D B1587J
TO-263-3 (S) (
Package
TO-220 TO-263 TO-252 LPDD
Temp.
0 C to 70 C 0 C to 70 C 0 C to 70 C 0 C to 70 C
TO-252 (D)
Bay Linear
1 2 3
1
2
3
ADJ/ GND
V OU VIN
T
Top View
Front View
LPDD (J)
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
Absolute Maximum Rating
Parameter
Maximum Input Voltage Power Dissipation Thermal Resistance Junction to Case Thermal Resistance Junction to Ambient Operating Junction Temperature Range Control Section Power Transistor Storage Temperature Range Lead Temperature (Soldering 10 Sec.)
Symbol
VIN PO JC JA TJ
Value
7 Internally Limited 3 50
Unit
V W C/W C
TSTG TLEAD
0 to 125 0 to 150 -65 to 150 260
Electrical Characteristics
(VIN = 4.75V to 5.25V; IO = 10mA to 4.0Amp, unless otherwise specified) Parameter Symbol Conditions
Output Voltage VO 0MIN
1.485 1.475 2.475 2.460 2.970 2.950 3.267 3.247 4.950 4.920 1.238 1.230
TYP
1.5 2.5 3.0 3.3 5.0 1.250 0.04 0.08 1.0 1.1 5 5 5 0.5 0.003 75 3.0 60 3.0 60
MAX
1.515 1.525 2.525 2.540 3.030 3.050 3.333 3.353 5.050 5.080 1.262 1.270 0.2 0.40 1.1 1.3 10 10
UNIT
V
Reference Voltage Line Regulation (1) Load Regulation (1) Dropout Voltage Minimum load Current Current Limit Ground Pin Current Temperature Stability Thermal Regulation Ripple Rejection Thermal Resistance
Vref REG (line) REG (LOAD) VD Imin IS IQ TS RA -
V %
60
3.0 60 3.0 60
V mA A mA % %/W dB C/W
Note: Output Switch tests are performed under pulsed conditions to minimize power dissipation
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
APPLICATION HINTS
The Bay Linear B1587 incorporates protection against over-current faults, reversed load insertion, over temperature operation, and positive and negative transient voltage. However, the use of an output capacitor is required in order to insure the stability and the performances. Stability The output capacitor is part of the regulator's frequency compensation system. Either a 220F aluminum electrolytic capacitor or a 47F solid tantalum capacitor between the output terminal and ground guarantees stable operation for all operating conditions. However, in order to minimize overshoot and undershoot, and therefore optimize the design, please refer to the section `Ripple Rejection'. Ripple Rejection Ripple rejection can be improved by adding a capacitor between the ADJ pin and ground. When ADJ pin bypassing is used, the value of the output capacitor required increases to its maximum (220F for an aluminum electrolytic capacitor, or 47F for a solid tantalum capacitor). If the ADJ pin is not bypass, the value of the output capacitor can be lowered to 100F for an electrolytic aluminum capacitor or 15F for a solid tantalum capacitor. However the value of the ADJ-bypass capacitor should be chosen with respect to the following equation: C = 1 / ( 6.28 * FR * R1 ) Where C = value of the capacitor in Farads (select an equal or larger standard value), FR = ripple frequency in Hz, R1 = value of resistor R1 in Ohms. If an ADJ-bypass capacitor is use, the amplitude of the output ripple will be independent of the output voltage. If an ADJ-bypass capacitor is not used, the output ripple will be proportional to the ratio of the output voltage to the reference voltage: M = VOUT / VREF Where M = multiplier for the ripple seen when the ADJ pin is optimally bypassed. VREF = Reference Voltage
Reducing parasitic resistance and inductance One solution to minimize parasitic resistance and inductance is to connect in parallel capacitors. This arrangement will improve the transient response of the power supply if your system requires rapidly changing current load condition. Thermal Consideration Although the B1587 offers some limiting circuitry for overload conditions, it is necessary not to exceed the maximum junction temperature, and therefore to be careful about thermal resistance. The heat flow will follow the lowest resistance path, which is the Junction-to-case thermal resistance. In order to insure the best thermal flow of the component, a proper mounting is required. Note that the case of the device is electrically connected to the output. In case the case has to be electrically isolated, a thermally conductive spacer can be used. However do not forget to consider its contribution to thermal resistance. Assuming: VIN = 10V, VOUT = 5V, IOUT = 4A, TA = 90C, CASE= 1C/W (no external heat sink, no wind) Power dissipation under these conditions PD = (VIN - VOUT) * IOUT = 15W Junction Temperature TJ = TA + PD * (CASE+ JC) For the Control Section TJ = 90C + 15W*(1C/W + 0.6C/W) = 114C 114C < TJUNCTION MAX for the control section. For the Power Section TJ = 90C + 15W*(1C/W + 1.6C/W) = 129C 129C < TJUNCTION MAX for the power transistor. In both case reliable operation is insured by adequate junction temperature.
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
Basic Adjustable Regulator
BAY B1587
V REF I
ADJ
V OU
T
V OU
T
R1
This current will go through the resistance R2 to set the overall output voltage. The current IADJ is very small and constant. Therefore its contribution to the overall output voltage is very small and can generally be ignored
Load Regulation
R2
50A
VOUT = V REF * ( 1 + R2/R1) + IADJ * R2
Fig.2 Basic Adjustable Regulator
Parasitic line resistance can degrade load regulation. In order not to affect the behavior of the regulator, it is best to connect directly the R1 resistance from the resistor divider to the case, and not to the load. For the same reason, it is best to connect the resistor R2 to the Negative side of the load.
Output Voltage Output Voltage
Output Voltage
Consider Figure 2. The resistance R1 generates a constant current flow, normally the specified load current of 10mA
VOUT
BAY B1587
RP Parasitic Line Resistance
Connect R1 to Case of Regulator
R1
RL R2
Connect R2 to Load
Fig.3 Basic Adjustable Regulator
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
VIN C1
IN
BAY B1587
ADJ
OUT
VIN IN C1
BAY B1587
ADJ
OUT C2 R1
VOUT
R1
LOAD
VOUT = VREF (1 + R2) + IADJ R2 R1
R2
Fig.4 4A Current Output Regulator
Fig 5. Typical Adjustable Regulator
(Note A)
VIN
+ 10F
IN
BAY
5V OUT
B1587
ADJ
VOUT
121 1% 150F
VIN
(Note A)
IN
BAY B1587
ADJ
OUT 121 1% +
5V
R1
+ 10F TTL Output 1k 2N3904 1k
100F
*C1 improves ripple rejection. XC should be ~ R1 at ripple frequency. Note A: VIN (MIN) = ( Intended VOUT ) + ( V DROPOUT (MAX) )
365 1%
R2
+
C1 10F*
365 1%
Note A: VIN (MIN) = ( Intended VOUT ) + ( V DROPOUT (MAX) )
Fig. 6
Improving Ripple Rejection
Fig.7
5V Regulator with Shutdown
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
TYPICAL CHARACTERISTICS
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
E b2 -AL2 -BA A1 C1 A
4 SEATING PLANE D 1 -C2 3 L3 L1 L H
b 3 PLCS
.010 M
AM
b1 e e1 D1 NOTES
1. 2. 3. 4.
c
8
A
C
TERM 4
E1
Refer To Applicable Symbol List. Dimensions And Tolerancing Per Ansi Y14.5m - 1982. Lead Dimension Uncontrolled in 3 . L Tab Contour Optional Within Dim. 2 & L2 And E1 & D1 b 5. D1 & E1 Establishes A Minimum Mounting Surface for Terminal 4. 6. L is the Termal Length for Soldering. 7. Controlling Dimension: Inch 8. 2 Mils Suggested For Postive Contact At Mounting.
BACK VIEW A-A
S Y M B O L A A1 b b1 b2 c c1 D D1 E E1 e e1 H L L1 L2 L3
INCHES MIN 0.086 0.035 0.025 0.300 0.205 0.018 0.018 0.235 0.170 0.250 0.170 0.098 0.180 0.370 0.020 0.025 0.035 0.045 0.410 0.040 0.050 0.060 9.398 0.508 0.635 0.889 1.143 MAX 0.094 0.045 0.035 0.045 0.215 0.023 0.023 0.245 0.265 MIN 2.184 0.889 0.635 7.620 5.207 0.457 0.457 5.969 4.318 6.350 4.318
MM MAX 2.3876 1.143 0.889 1.143 5.461 0.5842 0.5842 6.223 6.731 2.489 4.572 10.414 1.016 1.270 1.524
N O T E
4
4,5
4,5
6
4 3
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com
B1587
0.405 (10.287

0.005 0.127)
0.055 (1.397)
0.176 0.005 (4.470 0.050 0.002 (1.270

0.127) 0.051)
0.356 (9.042

0.005 0.127) 0.600 + 0.025 (15.24 0.635) 0.100 0.010 (2.540 0.254)
0.103 BSC (2.616)
0.050 (1.270) 0.032 + 0.001 (0.813 + 0.025) -
0.015 (0.381
+ + -
0.003 0.074) 0 8
Advance Information- These data sheets contain descriptions of products that are in development. The specifications are based on the engineering calculations, computer simulations and/ or initial prototype evaluation. Preliminary Information- These data sheets contain minimum and maximum specifications that are based on the initial device characterizations. These limits are subject to change upon the completion of the full characterization over the specified temperature and supply voltage ranges.
The application circuit examples are only to explain the representative applications of the devices and are not intended to guarantee any circuit design or permit any industrial property right to other rights to execute. Bay Linear takes no responsibility for any problems related to any industrial property right resulting from the use of the contents shown in the data book. Typical parameters can and do vary in different applications. Customer's technical experts must validate all operating parameters including " Typical" for each customer application.
LIFE SUPPORT AND NUCLEAR POLICY Bay Linear products are not authorized for and should not be used within life support systems which are intended for surgical implants into the body to support or sustain life, in aircraft, space equipment, submarine, or nuclear facility applications without the specific written consent of Bay Linear President.
Bay Linear, Inc
2478 Armstrong Street, Livermore, CA 94550 Tel: (925) 606-5950, Fax: (925) 940-9556
www.baylinear.com

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