4707 Dey Road Liverpool, N.Y. 13088
(315) 701-6751
FEATURES:
MIL-PRF-38534 QUALIFIED
171/172
HIGH POWER DUAL
OPERATIONAL AMPLIFIER
ISO-9001 CERTIFIED BY DSCC
M.S.KENNEDY CORP.
MSK172
MSK171
Half and Full Bridge Motor Drives
Audio Power Amplifiers
Bridge - 60W RMS Per Package
Stereo - 30W RMS Per Channel
Ideal for Single Supply Systems
5V - Peripheral
12V - Automotive
28V - Avionic
1
2
3
4
-Input 1
+Input 1
+Input 2
-Input 2
8
7
6
5
Output 1
-Vcc
+Vcc
Output 2
TYPICAL APPLICATIONS
PIN-OUT INFORMATION
Low Cost
Wide Supply Voltage Range: 5V to 40V
High Output Current: 3A Minimum
High Efficiency:
Vs-2.2V
at 2.5A
Internal Current Limit
Wide Common Mode Range
(Includes Negative Supply Voltage)
Low Distortion
Internal Output Snubbers for Ultra-Stable Operation
EQUIVALENT SCHEMATIC
The MSK 171/172 is a high power dual operational amplifier. Each amplifier is capable of delivering three amps of
current to the load. The MSK 171/172 is an excellent low cost alternative for bridge mode configurations since both
amplifiers are packaged together and will track thermally. The wide common mode range includes the negative rail,
facilitating single supply applications. It is possible to have a "ground based" input driving a single supply amplifier
with ground acting as the second or "bottom" supply of the amplifier. To maintain stability, output snubber networks
have been internally connected to each op amp output (see "amplifier stability" in the attached application notes).
The output stage is also current limit protected to approximately 3.0 amps. The MSK 171 is packaged in a space
efficient 8-pin power dip while the MSK 172 is packaged in an 8-pin z-pack power dip with heat sink attach tabs.
Consult factory for other packaging options if desired.
DESCRIPTION:
Rev. C 8/00
1
Input Bias Current
STATIC
Supply Voltage Range
INPUT
Offset Voltage
Offset Voltage Drift
Power Supply Rejection
Common Mode Rejection
Total Noise
OUTPUT
Output Voltage Swing
Output Current
Current Limit
Power Bandwidth
Crosstalk
Capacitive Load
TRANSFER CHARACTERISTICS
Slew Rate
Open Loop Voltage Gain
Total Supply Voltage
Output Current (within S.O.A.)
Input Voltage (Differential)
Input Voltage
(Common Mode)
Junction Temperature
-65C to +150C
300C
-55C to +125C
-40C to +85C
4.0C/W
40V
4A
V
CC
+V
CC
, -V
CC
-0.5V
150C
1
2
3
4
5
6
ABSOLUTE MAXIMUM RATINGS
T
ST
T
LD
T
C
R
TH
V
CC
I
OUT
V
IND
V
IN
T
J
Unless otherwise noted V
CC
=15VDC.
Devices shall be capable of meeting the parameter, but need not be tested. Typical parameters are for reference only.
Industrial grade devices shall be tested to subgroups 1 and 4 unless otherwise requested.
Military grade devices ('B' suffix) shall be 100% tested to subgroups 1,2,3 and 4.
Subgroup 5 and 6 testing available upon request.
Subgroup 1,4 T
C
=+25C
Subgroup 2,5 T
C
=+125C
Subgroup 3,6 T
A
=-55C
Storage Temperature
Lead Temperature
Case Operating Temperature
(MSK171B/172B)
(MSK171/172)
Thermal Resistance (DC)
Junction to Case
Group A
Subgroup
-
1
2
3
1
-
-
-
-
-
-
4
4
-
-
-
-
4
-
Typ.
15
35
75
45
0.5
20
35
75
80
85
0.1
14.2
4.0
4.0
13.6
68
0.22
1.2
100
Min.
2.5
-
-
-
-
-
-
-
60
60
-
14
3.0
-
-
60
-
0.5
80
Min.
2.5
-
-
-
-
-
-
-
60
60
-
14
3.0
-
-
-
-
0.5
80
Max.
20
75
-
-
10
-
1000
-
-
-
1.0
-
-
-
-
-
-
-
-
Typ.
15
35
-
-
2
20
35
75
80
85
0.1
14.2
4.0
4.0
13.6
68
0.22
1.2
100
Units
V
mA
mA
mA
mV
V/C
nA
nA
dB
dB
mV
V
A
A
KHz
dB
F
V/S
dB
MSK171B/172B
MSK171/172
2
Parameter
Max.
20
75
105
75
10
50
500
1000
-
-
1.0
-
-
-
-
-
-
-
-
Test Conditions
ELECTRICAL SPECIFICATIONS
1
2
NOTES:
Quiescent Current
2
2
2
2
2
2
2
(Split Supply)
Total; V
IN
=0V
V
IN
=0V
V
IN
=0V
V
CM
=0V
Full Temp.
V
CC
=15V
V
CM
=10VDC
R
L
=500
A
V
=1 C
L
=1500pF
(I
OUT
=0.5A)
V
OUT
=MAX
V
OUT
=28V
PP
I
OUT
=1A f=1KHz
A
V
=+1V/V
F=10Hz R
L
=500
Rev. C 8/00
2
APPLICATION NOTES
SAFE OPERATING AREA (SOA)
AMPLIFIER STABILITY
Since both output transistors in this amplifier are NPN, con-
sideration must be taken when stabilizing the output. A one
ohm resistor, 0.1uF capacitor snubber network has been added
internally from the output to -Vcc on each amplifier. This con-
figuration minimizes local output stage oscillations. As always,
adequate power supply bypassing is a necessity for ampli-
fier stability. A parallel combination of a 4.7uF electrolytic (for
every amp of output current) and a 0.01uF ceramic disc capaci-
tor should be connected as close as possible to the package
power supply pins to ground. The R-C snubber networks shown
on the outputs of the amplifiers in the typical circuits are inter-
nal and should not be added externally.
If the inductive load is driven near steady state conditions al-
lowing the output to drop more than 6V below the supply rail
while the amplifier is current limiting, the inductor should be
capacitively coupled or the supply voltage must be lowered to
meet the SOA criteria. It is a good practive to also connect
reverse biased fast recovery diodes to the output for protection
against sustained high energy flyback.
Vcc
20V
15V
10V
5V
Capacitive Load
200uF
500uF
5mF
50mF
Inductive Load
7.5mH
25mH
35mH
150mH
Safe operating area curves are a graphical representation of
all of the power limiting factors involved in the output stage of
an operational amplifier. Three major power limiting factors
are; output transistor wire bond carrying capability, output tran-
sistor junction temperature and secondary breakdown effects.
To see if your application is meeting or exceeding the limita-
tions of the safe operating area curves, perform the following
steps:
1.) Find the worst case output power dissipation. For a split
supply, purely resistive load application, this occurs when
V
OUT
=1/2 V
CC
.
2.) Take the values of (V
CC
-V
OUT
) and the corresponding out-
put current and find their intersection on the safe operating
area curves.
3.) Verify this point is below the safe operating area curves.
This is a simple task for purely resistive loads, for reactive loads
the following table will save extensive analysis. Under tran-
sient conditions, capacitive and inductive loads up to the fol-
lowing maximum are safe.
BIDIRECTIONAL MOTOR DRIVE
PARALLEL CONNECTION
(yields single 6A amplifier)
Rev. C 8/00
3
APPLICATION NOTES CONTINUED
HEAT SINKING
To determine if a heat sink is necessary for your appli-
cation and if so, what type, refer to the thermal model
and governing equation below.
Thermal
Model:
T
J
=P
D
x (R
JC
+ R
CS
+ R
SA
) + T
A
Where
T
J
= Junction Temperature
P
D
= 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
T
C
= Case Temperature
T
A
= Ambient Temperature
T
S
= Sink Temperature
Governing Equation:
1.) Find Driver Power Dissipation
P
D
= [(quiescent current) x (+V
CC
- (-V
CC
))] +
[(V
CC
-V
O
) x I
OUT
]
= (75mA) x (40V) + (10V) x (0.5A) + (10V) x (0.5A)
= 3W + 10W
= 13W
2.) For conservative design, set T
J
=+150C.
3.) For this example, worst case T
A
=+25C
4.) R
JC
= 4.0C/W typically
5.) R
CS
= 0.15C/W for most thermal greases
6.) Rearrange governing equation to solve for R
SA
R
SA
= ((T
J
- T
A
)/P
D
) - (R
JC
) - (R
CS
)
= ((150C - 25C) / 13W) - (4C/W) - (.15C/W)
5.5C/W
The heat sink in this example must have a thermal
resistance of no more than 5.5C/W to maintain a junc-
tion temperature of no more than +150C
.
Example:
In our example the amplifier application requires each
output to drive a 10 volt peak sine wave across a 20
ohm load for 0.5 amp of output current. For a worst
case analysis we will treat the 0.5 amp peak output cur-
rent as a D.C. output current. The power supplies are
20VDC.
Thermal Path:
Rev. C 8/00
4
TYPICAL PERFORMANCE CURVES
Rev. C 8/00
5
ORDERING INFORMATION
Screening Level
MECHANICAL SPECIFICATIONS
Part
Number
ESD TRIANGLE INDICATES PIN 1.
ALL DIMENSIONS ARE 0.010 INCHES UNLESS OTHERWISE LABELED.
Rev. C 8/00
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.
4707 Dey Road, Liverpool, New York 13088
Phone (315) 701-6751
FAX (315) 701-6752
www.mskennedy.com
MSK171
MSK171B
MSK172
MSK172B
Industrial
Military-Mil-PRF-38534
Industrial
Military-Mil-PRF-38534
MSK171
MSK172
6
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