4707 Dey Road Liverpool, N.Y. 13088
M.S.KENNEDY CORP.
(315) 701-6751
FEATURES:
SERIES
ISO-9001 CERTIFIED BY DSCC
Hermetic Surface Mount Package
Extremely Low Dropout Voltage: 425mV @ 7.5 Amps
Available in 1.5V, 1.7V, 1.9V, 2.5V, 3.3V, 5.0V and 12.0V
On Board Thermal Shut Down
Reverse Battery and Load Dump Protection
Low Ground Current: 120mA Typical at Full Load
1% Maximum Guaranteed Accuracy
Output Current to 7.5 Amps
Alternate Output Voltages Available
DESCRIPTION:
The MSK 5275 series voltage regulators are available in +1.5V, +1.7V, +1.9V, +2.5V, +3.3V, +5.0V and
+12.0V output configurations. All boast ultra low dropout specifications due to the utilization of a super PNP output
pass transistor with monolithic technology. Dropout voltages of 425mV at 7.5 amps are typical in this configuration,
which drives efficiency up and power dissipation down. Accuracy is guaranteed with a 1% maximum output voltage
tolerance. The MSK 5275 series is packaged in a space efficient 3 pin power surface mount ceramic package.
EQUIVALENT SCHEMATIC
5275
TYPICAL APPLICATIONS
PIN-OUT INFORMATION
High Efficiency, High Current Linear Regulators
Constant Voltage/Current Regulators
System Power Supplies
Switching Power Supply Post Regulators
Battery Powered Equipment
V
IN
V
OUT
Ground
1
2
3
1
Rev. D 1/02
MIL-PRF-38534 QUALIFIED
VERY HIGH CURRENT, LOW DROPOUT
SURFACE MOUNT
VOLTAGE REGULATORS
MSK5275-1.5
MSK5275-1.7
MSK5275-1.9
MSK5275-2.5
MSK5275-3.3
MSK5275-5.0
MSK5275-12
Input Voltage (100mS 1%D.C.)
Input Voltage
Enable Voltage
Output Current
-20V to +60V
26V
-0.3V to 26V
8A
Storage Temperature Range . . -65C to +150C
Lead Temperature . . . . . . . . . . . . . . . . . 300C
(10 Seconds Soldering)
Operating Temperature
MSK 5275 Series . . . . . . . . . -40C to +85C
MSK 5275H/E Series . . . . . . . -55to +125C
V
INP
V
IN
V
EN
I
OUT
T
ST
T
LD
T
J
ABSOLUTE MAXIMUM RATINGS
2
Rev. D 1/02
Output Current Limit 2
Output Noise 2
Thermal Resistance 2
Thermal Shutdown 2
V
OUT
= -1%; I
OUT
= 250 mA
V
OUT
= -1%; I
OUT
= 7.5A
V
IN
= V
OUT
+5V
10 mA
I
OUT
7.5A
(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
= 4A
V
IN
= V
OUT
+1V; I
OUT
= 7.5A
C
L
= 33F; 10 H
Z
f
100 KH
Z
Junction to Case
T
J
Ground Current
2 8
1
2, 3
1
1
1
2, 3
1
2, 3
-
-
-
-
-
-
Parameter
ELECTRICAL SPECIFICATIONS
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.5
1.0
80
425
0.2
0.3
0.05
0.5
9.5
35
120
260
1.0
130
1.0
2.0
200
600
1.0
2.0
0.5
1.0
15
75
-
-
1.2
-
%
%
mV
mV
%
%
%
%
A
mA
mA
V
C/W
C
-
-
-
-
-
-
-
-
-
-
-
-
-
-
0.5
-
80
425
0.2
0.3
0.05
0.5
9.5
35
120
260
1.0
130
1.0
-
225
625
1.2
-
0.6
-
15
80
-
-
1.5
-
Group A
Subgroup
MSK 5275H/E SERIES
Min. Typ. Max.
MSK 5275 SERIES
Min. Typ. Max.
Units
Test Conditions 1 3
Output Voltage Tolerance
Dropout Voltage 2
Load Regulation
Line Regulation
I
OUT
= 10mA; V
IN
= V
OUT
+1V
+1.5V
+1.7V
+1.9V
+2.5V
+3.3V
+5.0V
+12.0V
OUTPUT
VOLTAGE
7
PART
NUMBER
1
2
3
4
5
6
7
8
NOTES:
Output decoupled to ground using 33F 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
Subgroup 2
Subgroup 3
Please consult the factory if alternate output voltages are required.
The MSK 5275-1.5, MSK 5275-1.7, MSK 5275-1.9 and MSK 5275-2.5 have an additional 10 mA of Quiescent Current.
T
C
= +25C
T
J
= +125C
T
A
= -55C
]
APPLICATION NOTES
REGULATOR PROTECTION:
The MSK 5275 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.
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 5275 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:
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.
OUTPUT CAPACITOR:
The output voltage ripple of the MSK 5275 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 33F 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.
3
Rev. D 1/02
1.7W
PACKAGE CONNECTIONS:
The MSK 5275 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.
HEAT SINK SELECTION:
To select a heat sink for the MSK 5275, the following
formula for convective heat flow may be used.
Governing Equation:
Tj = Pd x (R
jc + R
cs + R
sa) + Ta
WHERE:
Tj = Junction Temperature
Pd = Total Power Dissipation
R
jc = Junction to Case Thermal Resistance
R
cs = Case to Heat Sink Thermal Resistance
R
sa = 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 125C. The equation may now be rearranged to
solve for the required heat sink to ambient thermal resis-
tance (R
sa).
EXAMPLE:
An MSK 5275-3.3 is configured for Vin=+5V and
Vout=+3.3V. Iout is a continuous 1A DC level. The
ambient temperature is +25C. The maximum desired
junction temperature is 125C.
R
jc = 1.0C/W and R
cs = 0.5C/W typically.
Power Dissipation = (5V - 3.3V) x (1A)
= 1.7 Watts
Solve for R
sa:
R
sa = 125C - 25C - 1.0C/W - 0.5C/W
In this example, a heat sink with a thermal resistance of
no more than 57C/W must be used to maintain a junc-
tion temperature of no more than 125C.
= 57.32C/W
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