MIL-PRF-38534 AND 38535 CERTIFIED FACILITY
M.S.KENNEDY CORP.
FEATURES:
HIGH POWER
OPERATIONAL AMPLIFIER
115
High Output Current - 15A peak
Ultra Low Thermal Resistance - 0.5°C/W Typ.
Excellent Linearity - Class A/B Output
Wide Supply Range - ±10V to ±50V
High Output Power Dissipation Capability
Output Short Circuit Protected
User Programmable Current Limit
Isolated Case Allows Direct Heat Sinking
Low Quiescent Current -±22mA. Typ.
Contact MSK for MIL-PRF-38534 Qualification Status
DESCRIPTION:
The MSK115 is a High Power Operational Amplifier. Due to the extremely low thermal resistance from the transistor
junctions to the case, the MSK115 can dissipate extreme amounts of power at a case temperature of 125°C. The amplifier
is packaged in a hermetic plug in power package with isolated, bolt down tabs.
EQUIVALENT SCHEMATIC
EQUIVALENT SCHEMATIC
TYPICAL APPLICATIONS
TYPICAL APPLICATIONS
Magnetic Deflection Circuit Driver
Programmable Power Supplies
Motor, Valve and Actuator Control
Audio Amplifier
1
2
3
4
5
6
1
PIN-OUT INFORMATION
+V
CC
Balance
Inverting Input
Non-Inverting Input
Balance
-V
CC
12
11
10
9
8
7
+V
C
+Current Limit
Output
Output
-Current Limit
-V
C
8548-119 Rev. E 4/14
ABSOLUTE MAXIMUM RATINGS
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8
ELECTRICAL SPECIFICATIONS
Parameter
STATIC
Supply Voltage Range
Quiescent Current
3
Test Conditions
1
Group A
Subgroup Min.
-
MSK115B
Typ.
Max.
Min.
MSK115
Typ.
Max.
±10
-
-
-
-
±22
±28
0.5
±50
±35
±45
0.6
±10
-
-
-
-
±22
-
0.5
±45
±40
-
0.7
V
IN
=0V
A
V
=-10V/V
1
2,3
-
Thermal Resistance
INPUT
Input Offset Voltage
3
Junction to Case @ 25°C
V
IN
=0V
A
V
=10V/V
1
2,3
7
8A,8B
1
2,3
1
2,3
-
-
±2
±3
±6
±12
-
-
±2
-
±10
-
Bal.Pins=NC
Input Offset Adjust
R
POT
=10KΩ Wiper to -V
CC
A
V
=-10V/V
Input Bias Current
V
CM
=0V
Either Input
Input Offset Current
V
CM
=0V
Adjust to zero
Adjust to zero
-
-
-
-
50
-
80
±10
±15
±5
±10
250
±35
100
±30
±250
±30
±100
-
-
-
-
-
-
-
-
35
-
74
Adjust to zero
-
±10
-
±5
-
250
±35
100
-
±50
-
±50
-
-
-
-
Input Impedance
3
3
F=DC
-
-
Common Mode Range
Common Mode Rejection Ratio
3
OUTPUT
Output Voltage Swing
3
F=100Hz
V
CM
=±5V
-
R
L
=500Ω
A
V
=-10V/V
4
-
4
-
±35
±35
15
-
±37
±36
-
2
-
-
-
-
±33
±33
10
-
±37
±36
-
5
-
-
-
-
R
L
=10Ω R
SC
=
0Ω
A
V
=-10V/V
V
OUT
=MAX
0.1% 10V step
Output Current, Peak
Settling Time
2 3
TRANSFER CHARACTERISTICS
Slew Rate
Open Loop Voltage Gain
Gain Bandwidth Product
3
3
V
OUT
=±10V R
L
=500Ω A
V
=-10V/V
R
L
=500Ω F=10Hz
R
L
=10Ω F=1 MHz
4
4
-
2.5
95
-
5
105
4
-
-
-
1
85
-
2.5
105
3
-
-
-
NOTES:
Unless otherwise specified, ±V
CC
=±40V
DC
AV= -1, measured in false summing junction circuit.
Guaranteed by design but not tested. Typical parameters are representative of actual device performance but are for reference only.
Industrial grade devices shall be tested to subgroups 1,4 and 7 unless otherwise specified.
Military grade devices ("B" suffix) shall be 100% tested to subgroups 1,2,3,4,7,8A and 8B.
Subgroups 5 and 6 testing available upon request.
Subgroup 1,4,7 T
A
=T
C
=+25°C
Subgroup 2,5,8A T
A
=T
C
=+125°C
Subgroup 3,6,8B T
A
=T
C
=-55°C
8 Continuous operation at or above absolute maximum ratings may adversely effect the device performance and/or life cycle.
9 Internal solder reflow temperature is 180°C, do not exceed.
1
2
3
4
5
6
7
2
8548-119 Rev. E 4/14
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±V
CC
I
OUT
V
IN
T
C
Supply Voltage
±50V
Output Current
15A
Differential Input Voltage
±37V
Case Operating Temperature Range
(MSK115B)
-55°C to+125°C
(MSK115)
-40°C to +85°C
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T
ST
Storage Temperature Range
T
LD
Lead Temperature Range
(10 Seconds)
P
D
Power Dissipation
T
J
Junction Temperature
9
-65°C to +150°C
300°C
See S0A Curve
175°C
Units
V
mA
mA
°C/W
mV
mV
mV
mV
nA
nA
nA
nA
MΩ
V
dB
V
V
A
μS
V/μS
dB
MHz
APPLICATION NOTES
HEAT SINKING
To determine if a heat sink is necessary for your application and
if so, what type, refer to the thermal model and governing equation
below.
CURRENT LIMIT
The MSK115 has an on-board current limit scheme designed to
shut off the output drivers anytime output current exceeds a prede-
termined limit. The following formula may be used to determine the
value of current limit resistance necessary to establish the desired
current limit.
R
CL
=(OHMs)=(0.65 volts/current limit in amps) - 0.01OHM
The 0.01 ohm term takes into account any wire bond and lead
resistance. Since the 0.65 volt term is obtained from the base emit-
ter voltage drop of a bipolar transistor: the equation only holds true
for operation at +25°C case temperature. The curve below illus-
trates the effect of case temperature on current limit.
Thermal Model:
Governing Equation:
T
J=
P
D
x
(R
θJC
+
R
θCS
+
R
θSA
)
+
T
A
Where
T
J=
Junction Temperature
P
D=
Total Power Dissipation
R
θJC=
Junction to Case Thermal Resistance
R
θCS=
Case to Heat Sink Thermal Resistance
R
θSA=
Heat Sink to Ambient Thermal Resistance
T
C=
Case Temperature
T
A=
Ambient Temperature
T
S=
Sink Temperature
POWER SUPPLY BYPASSING
Both the negative and the positive power supplies must be
effectively decoupled with a high and low frequency bypass circuit
to avoid power supply induced oscillation. An effective decoupling
scheme consists of a 0.1 microfarad ceramic capacitor in parallel
with a 4.7 microfarad tantalum capacitor from each power supply
pin to ground. It is also a good practice with very high power
op-amps, such as the MSK115, to place a 30-50 microfarad non-
electrolytic capacitor with a low effective series resistance in par-
allel with the other two power supply decoupling capacitors. This
capacitor will eliminate any peak output voltage clipping which may
occur due to poor power supply load regulation. All power supply
decoupling capacitors should be placed as close to the output stage
power supply pins as possible (pins 7 and 12).
Example
:
In our example the amplifier application requires the output to
drive a 20 volt peak sine wave across a 20 ohm load for 1 amp of
output current. For a worst case analysis we will treat the 1 amp
peak output current as a D.C. output current. The power supplies
are ±40 VDC.
1.) Find Power Dissipation
P
D
=[(quiescent current) x (V
S
-(V
S
))]+[(+V
S
-V
O
) x I
OUT
]
=(25mA) x (80V)+(20V) x (1A)
=2W+20W
=22W
2.) For conservative design, set T
J
=+125°C
3.) For this example, worst case T
A
=+50°C
4.) R
θJC
=0.55°C/W from MSK 115B Data Sheet
5.) R
θCS
=0.15°C/W for most thermal greases
6.) Rearrange governing equation to solve for R
θSA
R
θSA
=((
T
J
-
T
A
)/
P
D
) - (
R
θJC
) - (
R
θCS
)
=((125°C -50°C)/22W) - (0.55°C/W) - (0.15°C/W)
=2.71°C/W
The heat sink in this example must have a thermal resistance of
no more than 2.71°C/W to maintain a junction temperature of no
more than +125°C.
BALANCE PINS
Pins 2 & 5 of the MSK115 are used to null unwanted input offset
voltage. Connect as shown in the typical connection schematic. If
the balance pins are not used, they should be left open/not con-
nected.
3
8548-119 Rev. E 4/14
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