ISO-9001 CERTIFIED BY DSCC
M.S.KENNEDY CORP.
FEATURES:
VERY HIGH CURRENT, LOW DROPOUT
SURFACE MOUNT
VOLTAGE REGULATORS
5250
SERIES
4707 Dey Road Liverpool, N.Y. 13088
Hermetic Surface Mount Package
Extremely Low Dropout Voltage: 370mV @ 5 Amps
Available in 2.5V, 3.3V, 5.0V and 12.0V
On Board Thermal Shut Down
Reverse Battery and Load Dump Protection
Low Ground Current: 70mA Typical at Full Load
1% Maximum Guaranteed Accuracy
Output Current to 5 Amps
Alternate Output Voltages Available
(315) 701-6751
MIL-PRF-38534 QUALIFIED
DESCRIPTION:
The MSK 5250 series voltage regulators are available in +2.5V, +3.3V, +5.0V, and +12.0V output configura-
tions. All boast ultra low dropout specifications due to the utilization of a super PNP output pass transistor with
monolithic technology. Dropout voltages of 370mV at 5 amps are typical in this configuration, which drives effi-
ciency up and power dissipation down. Accuracy is guaranteed with a 1% maximum output voltage tolerance. The
MSK 5250 series is packaged in a space efficient 3 pin power surface mount ceramic package.
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
High Efficiency, High Current Linear Regulators
Constant Voltage/Current Regulators
System Power Supplies
Switching Power Supply Post Regulators
Battery Powered Equipment
1
PIN-OUT INFORMATION
1 V
IN
2 V
OUT
3 Ground
Rev. B 7/00
ABSOLUTE MAXIMUM RATINGS
V
INP
V
IN
V
EN
I
OUT
Input Voltage (100mS 1%D.C.) -20V to +60V
Input Voltage
26V
Enable Voltage
-0.3V to 26V
Output Current
5.5A
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T
ST
T
LD
T
J
Storage Temperature Range
Lead Temperature . . . . . . .
(10 Seconds Soldering)
Operating Temperature
MSK 5250 Series . . . . . . .
MSK 5250H Series . . . . . .
. . -65°C to +150°C
. . . . . . . . . . 300°C
. . -40°C to +85°C
. -55°C to +125°C
ELECTRICAL SPECIFICATIONS
Parameter
Output Voltage Tolerance
Test Conditions 1 3
I
OUT
= 10mA; V
IN
= V
OUT
+1V
∆V
OUT
= -1%; I
OUT
= 100 mA
∆V
OUT
= -1%; I
OUT
= 5A
V
IN
= V
OUT
+5V
10 mA
≤
I
OUT
≤
5A
(V
OUT
+1V)
≤
V
IN
≤
26V
I
OUT
= 10 mA
V
OUT
= 0V; V
IN
= V
OUT
+1V
V
IN
= V
OUT
+1V; I
OUT
= 2.5A
V
IN
= V
OUT
+1V; I
OUT
= 5A
C
L
= 20µF; 10 H
Z
≤
f
≤
100 KH
Z
Junction to Case
T
J
Group A
Subgroup
1
2, 3
1
1
1
2, 3
1
2, 3
-
-
-
-
-
-
MSK 5250H SERIES
Min.
Typ.
Max.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
±0.5
±1.0
80
370
±0.2
±0.3
±0.05
±0.5
7.5
15
70
400
1.5
130
±1.0
±2.0
175
600
±1.0
±2.0
±0.5
±1.0
10
50
-
-
2.0
-
MSK 5250 SERIES
Min. Typ. Max.
-
-
-
-
-
-
-
-
-
-
-
-
-
-
±0.5
-
80
370
±0.2
±0.3
±0.05
±0.5
7.5
15
70
400
1.5
130
±1.0
-
200
625
±1.2
-
±0.6
-
10
55
-
-
2.2
-
Units
%
%
mV
mV
%
%
%
%
A
mA
mA
µV
°C/W
°C
Dropout Voltage
2
Load Regulation
Line Regulation
Output Current Limit 2
Ground Current
Output Noise 2
Thermal Resistance 2
Thermal Shutdown 2
2 8
PART
NUMBER
MSK5250-2.5
MSK5250-3.3
MSK5250-5.0
MSK5250-12
OUTPUT
VOLTAGE
7
+2.5V
+3.3V
+5.0V
+12.0V
NOTES:
1 Output decoupled to ground using 20µF minimum capacitor unless otherwise specified.
2 This parameter is guaranteed by design but need not be tested.
Typical parameters are representative of actual device performance but are for reference only.
3 All output parameters are tested using a low duty cycle pulse to maintain TJ = TC.
4 Industrial grade devices shall be tested to subgroup 1 unless otherwise specified.
5 Military grade devices ('H' suffix) shall be 100% tested to subgroups 1,2,3.
6 Subgroup 1 T
C
= +25°C
Subgroup 2 T
J
= +125°C
Subgroup 3 T
A
= -55°C
7 Please consult the factory if alternate output voltages are required.
8 The MSK 5250-2.5 has an additional 10 mA of Quiescent Current.
2
Rev. B 7/00
APPLICATION NOTES
REGULATOR PROTECTION:
The MSK 5250 series is fully protected against reversed
input polarity, overcurrent faults, overtemperature con-
ditions (Pd) and transient voltage spikes of up to 60V. If
the regulator is used in dual supply systems where the
load is returned to a negative supply, the output voltage
must be diode clamped to ground.
PACKAGE CONNECTIONS:
The MSK 5250 series are highly thermally conductive
devices and the thermal path from the package heat sink
to the internal junctions is very short. Standard surface
mount soldering techniques should be used when mount-
ing the device. Some applications may require additional
heat sinking of the device.
OUTPUT CAPACITOR:
The output voltage ripple of the MSK 5250 series volt-
age regulators can be minimized by placing a filter ca-
pacitor from the output to ground. The optimum value
for this capacitor may vary from one application to the
next, but a minimum of 20µF is recommended for opti-
mum performance. Transient load response can also be
improved by placing a capacitor directly across the load.
The capacitor should not be an ultra-low ESR type. Tan-
talum capacitors are best for fast load transients but
aluminum electrolytics will work fine in most applica-
tions.
HEAT SINK SELECTION:
To select a heat sink for the MSK 5250, the following
formula for convective heat flow may be used.
Governing Equation:
Tj = Pd x (Rθjc + Rθcs + Rθsa) + Ta
WHERE:
Tj = Junction Temperature
Pd = Total Power Dissipation
Rθjc = Junction to Case Thermal Resistance
Rθcs = Case to Heat Sink Thermal Resistance
Rθsa = Heat Sink to Ambient Thermal Resistance
Ta = Ambient Temperature
First, the power dissipation must be calculated as fol-
lows:
Power Dissipation = (Vin - Vout) x Iout
Next, the user must select a maximum junction tempera-
ture. The absolute maximum allowable junction tempera-
ture is 125°C. The equation may now be rearranged to
solve for the required heat sink to ambient thermal resis-
tance (Rθsa).
EXAMPLE:
An MSK 5250-3.3 is configured for Vin=+5V and
Vout=+3.3V. Iout is a continuous 1A DC level. The
ambient temperature is +25°C. The maximum desired
junction temperature is 125°C.
Rθjc = 1.5°C/W and Rθcs = 0.5°C/W typically.
Power Dissipation = (5V - 3.3V) x (1A)
= 1.7 Watts
Solve for Rθsa:
Rθsa = 125°C - 25°C - 1.5°C/W - 0.5°C/W
1.7W
LOAD CONNECTIONS:
In voltage regulator applications where very large load
currents are present, the load connection is very impor-
tant. The path connecting the output of the regulator to
the load must be extremely low impedance to avoid af-
fecting the load regulation specifications. Any imped-
ance in this path will form a voltage divider with the
load. The MSK 5250 series requires a minimum of 10mA
of load current to stay in regulation.
MINIMIZING POWER DISSIPATION:
Many applications can not take full advantage of the
extremely low dropout specifications of the regulator due
to large input to output voltage differences. The simple
circuit below illustrates a method to reduce the input
voltage at the regulator to just over the dropout specifi-
cation to keep the internal power dissipation minimized:
[
]
= 56.82°C/W
For a given continuous maximum load of 1 amp, R1 can
be selected to drop the voltage seen at the regulator to
4V. This allows for the output tolerance and dropout
specifications. Input voltage variations (5V) also should
be included in the calculations. The resistor should be
sized according to the power levels required for the ap-
plication.
In this example, a heat sink with a thermal resistance of
no more than 56°C/W must be used to maintain a junc-
tion temperature of no more than 125°C.
3
Rev. B 7/00
TYPICAL PERFORMANCE CURVES
4
Rev. B 7/00
MECHANICAL SPECIFICATIONS
NOTE:
ALL DIMENSIONS ARE ±0.010 INCHES UNLESS OTHERWISE LABELED.
ORDERING INFORMATION
MSK5250-3.3 H
SCREENING
BLANK= INDUSTRIAL; H= MIL-PRF-38534
OUTPUT VOLTAGE
2.5=+2.5V; 3.3=+3.3V; 5.0=+5.0V; 12=+12.0V
GENERAL PART NUMBER
The above example is a +3.3V, Military regulator.
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.
M.S. Kennedy Corp.
5
Rev. B 7/00
