ISO-9001 CERTIFIED BY DSCC
M.S.KENNEDY CORP.
POSITIVE ADJUSTABLE, LOW DROPOUT
SURFACE MOUNT
VOLTAGE REGULATORS
5231
4707 Dey Road Liverpool, N.Y. 13088
(315) 701-6751
FEATURES:
MIL-PRF-38534 QUALIFIED
Hermetic Surface Mount Package
Low Dropout Voltage: 1.5V @ 2 Amps
Adjustable Output Voltage
On Board Thermal Overload Protection
Short Circuit Current Limiting
Output Current to 3 Amps
Second Source for 0M185
Pin Compatible with the OM7628NM
DESCRIPTION:
The MSK 5231 voltage regulator is a positive adjustable regulator that with proper heatsinking, can provide 3 Amps
of output current. Low dropout and impressive thermal characteristics help to improve efficiency and lower power
dissipation. An accurate reference voltage allows for precise output adjustment. The MSK 5231 is packaged in a
hermetic, space efficient 3 pin power surface mount ceramic package.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
PIN-OUT INFORMATION
1 VIN
2 Adjust
3 VOUT
High Efficiency, High Current Linear Regulators
Constant Current Regulators
System Power Supplies
Switching Power Supply Post Regulators
Battery Chargers
1
Rev. - 7/02
ABSOLUTE MAXIMUM RATINGS
VIN
IOUT
PD
35V
Input to Output Voltage Differential
4A
Output Current
Internally Limited
Power Dissipation
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Storage Temperature Range
Lead Temperature
(10 Seconds Soldering)
Operating Temperature
MSK 5231
MSK 5231H/E
TST
TLD
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TJ
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-65°C to +150°C
300°C
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-40°C to+85°C
-55°to+125°C
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ELECTRICAL SPECIFICATIONS
Parameter
Reference Voltage
(VIN-VOUT)=3V IOUT=10mA
1
1.238
1.250
1.262
1.230
1.250
1.270
V
1
1.220
1.250
1.270
1.215
1.250
1.275
V
2,3
1.220
1.250
1.270
-
-
-
V
1
-
1.3
1.5
-
1.3
1.5
V
2,3
-
1.3
1.5
-
-
-
V
1.5V ≤ (VIN-VOUT) ≤ 15V IOUT=10mA
1
-
0.02
0.2
-
0.02
0.4
%
15V ≤ (VIN-VOUT) ≤ 35V IOUT=10mA
2,3
-
0.05
0.5
-
-
-
%
1
-
0.1
0.8
-
0.1
1.0
%
2,3
-
0.2
1.0
-
-
-
%
1
3.2
4.0
2
3.2
4.0
-
A
2,3
3.2
4.0
-
-
-
-
A
1
0.2
0.5
-
0.2
0.5
-
A
2,3
0.2
0.5
-
-
-
-
A
4
60
75
-
60
75
-
dB
1
-
55
120
-
55
120
µA
2,3
-
55
120
-
-
-
µA
1
-
5
10
-
5
10
mA
2,3
-
5
10
-
-
-
mA
30mS pulse TA=25°C
1
-
0.004
0.02
-
0.004
0.02
%/W
-55°C ≤ TJ ≤ +125°C
-
-
0.5
-
-
0.5
-
%
Junction to Case @ 125°C
-
-
0.8
1.5
-
0.8
1.7
°C/W
IOUT=2.0A ∆VREF=1%
Line Regulation
Load Regulation
VIN-VOUT=3V 10mA ≤ IOUT ≤ 2.0A
VIN-VOUT=5.0V
Current Limit
MSK 5231
Typ.
Max.
Group A
Subgroup
1.5V ≤ (VIN-VOUT) ≤ 25V 10mA ≤ IOUT ≤ 2.0A
Dropout Voltage 2
MSK 5231H/E
Min.
Typ.
Max.
Test Conditions 1 4
2
VIN-VOUT=25V
Min.
Units
F=120Hz CADJ=25µF
Ripple Rejection 2
COUT=25µF IOUT=2.0A
VIN-VOUT=3.0V
Adjust Pin Current
1.5V ≤ (VIN-VOUT) ≤ 25V 10mA ≤ IOUT ≤ 2.0A
Minimum Load Current 2
Thermal Regulation 2
Temperature Stability
Thermal Resistance 2
2
(VIN-VOUT)=24V
NOTES:
1
2
3
4
5
6
7
Output decoupled to ground using 20µF minimum capacitor unless otherwise specified.
This parameter is guaranteed by design but need not be tested.
Typical parameters are representative of actual device performance but are for reference only.
All output parameters are tested using a low duty cycle pulse to maintain TJ = TC.
Industrial grade and "E" suffix devices shall be tested to subgroup 1 unless otherwise specified.
Military grade devices ('H' suffix) shall be 100% tested to subgroups 1,2,3.
Subgroup 1,4 TA=TC=+25°C
2,5 TA=TC=+125°C
3,6 TA=TC=-55°C
2
Rev. - 7/02
APPLICATION NOTES
OVERLOAD SHUTDOWN
In this case the result is 10.0°C/W. Therefore, a heat
sink with a thermal resistance of no more than 10.0°C/
W must be used in this application to maintain regulator
circuit junction temperature under 125°C.
The MSK 5231 features both power and thermal overload protection. When the maximum power dissipation
is not exceeded, the regulator will current limit slightly
above its 3 amp rating. As the VIN-VOUT voltage increases,
however, shutdown occurs in relation to the maximum
power dissipation curve. If the device heats enough to
exceed its related die junction temperature due to excessive ambient temperature, improper heat sinking etc.,
the regulator shuts down until an appropriate junction
temperature is maintained. It should also be noted that
in the case of an extreme overload, such as sustained
direct short, the device may not be able to recover. In
these instances, the device must be shut off and power
reapplied to eliminate the shutdown condition.
STABILITY
For stable operation in most applications it is recommended that a 10µf tantalum capacitor be used at the
input of the regulator. In addition, if the regulator is not
located very close to the power supply filter capacitors,
a 4.7µf low ESR tantalum capacitor should be added to
the regulator's input. Electrolytic capacitors may also be
used. When substituting an electrolytic in place of a tantalum the value should be increased by a factor of ten
over the tantalum value.
The output of the regulator should be bypassed using
a minimum 10µf tantalum capacitor. To ensure good transient response under heavy load conditions the output
capacitor may be increased without limit. Larger capacitance values will further improve stability and transient
response.
HEAT SINKING
To determine if a heat sink is required for your application and if so, what type, refer to the thermal model and
governing equation below.
Governing Equation: Tj=Pd x (Rθjc + Rθcs +Rθsa)+ Ta
WHERE
Tj = Junction Temperatre
Pd = Total Power Dissipation
Rθjc = Junction to Case Thermal Resistance
Rθcs = Case to Heat Sink Thermal Resistance
Rθsa = Heat Sink to Ambient Thermal Resistance
Tc = Case Temperature
Ta = Ambient Temperature
Ts = Heat Sink Temperature
LOAD REGULATION
Load regulation will be limited by the resistance of the
wire connecting the regulator to the load. For example,
if 20 gauge wire were used which has a resistance of
approximately 0.008 ohms per foot, this would result in
a voltage drop of 8mV/ft at 1 amp of load current. Also,
best load regulation will be seen when the adjust resistor, R1, is connected directly to the regulator and not to
the load. In addition, it is important to follow the capacitor selection guidelines for stability and load regulation
performance.
EXAMPLE:
This example demonstrates an analysis where the regulator is at one-half of its maximum rated power dissipation, which occurs when the output current is at 1.5
amps.
OUTPUT VOLTAGE
The MSK 5231 requires two external resistors to set
the output voltage. A 1.25 volt reference voltage is developed between the output and adjust pins. Resistor,
R1, is placed between these pins with a second resistor,
R2, placed from the adjust pin to ground. A constant
current will flow from the output through these two
resitors to set the output voltage. The series resistance
of R1 & R2 should be selected to provide a minimum
load current of 10mA.
VIN=+7.0V VOUT=+5.0V
IOUT=1.5A
1.) Assume 45° heat spreading model.
2.) Find power dissipation:
Pd=(VIN-VOUT) (IOUT)
Pd=(7-5) (1.5)
=3.0W
3.) For conservative design, set TJ=+125°C Max.
4.) For this example, worst case TA=+90°C.
5.) RθJC=1.5°C/W from the Electrical Specification Table.
6.) RθCS=0.15°C/W for most thermal greases.
7.) Rearrange governing equation to solve for RθSA:
RθSA= ((TJ - TA)/Pd) - (RθJC) - (RθCS)
= (125°C - 90°C)/3.0W - 1.5°C/W - 0.15°C/W
= 10.0°C/W
3
Rev. - 7/02
TYPICAL PERFORMANCE CURVES
4
Rev. - 7/02
MECHANICAL SPECIFICATIONS
NOTE: ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.
ORDERING INFORMATION
MSK5231 H
SCREENING
BLANK= INDUSTRIAL; E=EXTENDED RELIABILITY
H= MIL-PRF-38534 CLASS H
GENERAL PART NUMBER
M.S. Kennedy Corp.
4707 Dey Road, Liverpool, New York 13088
Phone (315) 701-6751
FAX (315) 701-6752
www.mskennedy.com
The information contained herein is believed to be accurate at the time of printing. MSK reserves the right to make
changes to its products or specifications without notice, however, and assumes no liability for the use of its products.
Please visit our website for the most recent revision of this datasheet.
5
Rev. - 7/02