PowerAmp Design
POWER OPERATIONAL AMPLIFIER
PAD38
Rev B
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HIGH VOLTAGE – 200 VOLTS
HIGH CURRENT – 10 AMPS
125 WATT DISSIPATION CAPABILITY
HIGH SLEW RATE- 10V/µS
FOUR WIRE CURRENT LIMIT
APPLICATIONS
LINEAR AND ROTARY MOTOR DRIVE
YOKE/MAGNETIC FIELD EXCITATION
PROGRAMMABLE POWER SUPPLIES
INDUSTRIAL (PA) AUDIO
DESCRIPTION
The PAD38 is a power operational amplifier
constructed with surface mount components to
provide a cost effective solution for many
industrial applications. With a footprint only 3.3in2
the PAD38 offers outstanding performance that
rivals more expensive hybrid component
amplifiers or rack-mount amplifiers. User
selectable external compensation tailors the
amplifier’s
response
to
the
application
requirements. Programmable current limit is builtin. The amplifier circuitry is built on a thermally
conductive but electrically insulating substrate. No
BeO is used in the PAD38. The resulting module
is a small, high performance solution for many
industrial applications.
Power Amp Design  3381 W Vision Dr  Tucson AZ 85742  USA  Phone (520)579-3441  Fax (208)279-5458  Web Site: www.PowerAmpDesign.net
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
PowerAmp Design  PAD38  POWER OPERATIONAL AMPLIFIER
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KEY FEATURES
POWER OPERATIONAL AMPLIFIER
PAD38
CIRCUIT & CONNECTIONS
EQUIVALENT CIRCUIT
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
PINOUT & CONNECTIONS
Cc
3
2
1
9 10 11 12 13 14
4
6
7 8
5
+VB GND NC Cc2 NC Cc1 NC NC NC NC NC
+Vs
C2
+
C1
VIEW FROM COMPONENT SIDE
-ILIM
NC NC
-Vs
-IN +IN GND NC -VB IQ +ILIM
30 29 28 27 26 25 24 23 22 21 20 19 18
RS
OUT
17 16 15
TO FEEDBACK
& LOAD
-Vs
C4
PHASE COMPENSATION TYP. SLEW RATE
GAIN
Cc
1
470pF
4V/uS
3
220pF
9V/uS
> 5
100pF
15V/uS
> 12
47pF
20V/uS
+
C3
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
2
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
PAD38 POWER OPERATIONAL AMPLIFIER
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
__________________________________________________________________________________
SUPPLY VOLTAGE, +Vs to −Vs
BOOST VOLTAGE,
OUTPUT CURRENT, within SOA
POWER DISSIPATION, internal, DC
INPUT VOLTAGE, differential
INPUT VOLTAGE, common mode
TEST CONDITIONS1
PARAMETER
OFFSET VOLTAGE
OFFSET VOLTAGE vs. temperature
OFFSET VOLTAGE vs. supply
3
BIAS CURRENT, initial
BIAS CURRENT vs. supply
OFFSET CURRENT, initial
INPUT RESISTANCE, DC
INPUT CAPACITANCE
COMMON MODE VOLTAGE RANGE
COMMON MODE VOLTAGE RANGE
COMMON MODE REJECTION, DC
NOISE
100kHz bandwidth, 1kΩ RS
OPEN LOOP
GAIN BANDWIDTH PRODUCT @ 1MHz
PHASE MARGIN
RL= 10kΩ, CC=100pF
CC=100pF
Full temperature range
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING
CURRENT, continuous, DC
SLEW RATE, AV = −10
SETTLING TIME, to 0.1%
RESISTANCE
IO = 10A
IO = −10A
+VB=+Vs+10V, IO = 10A
-VB=-Vs-10V, IO = -10A
GAIN
OUTPUT
5
RESISTANCE, AC, junction to air
RESISTANCE, DC junction to air, outputs
TEMPERATURE RANGE, heat sink
TYP
MAX
1
20
3
50
20
100
0.1
50
100
4
VOLTAGE
CURRENT, quiescent, boost supply
CURRENT, total
THERMAL
MIN
Full temperature range
CC = 100pF
2V Step, CC = 100pF
No load, DC
POWER SUPPLY
TEMPERATURE, pin solder, 10s
TEMPERATURE, junction2
TEMPERATURE RANGE, storage
OPERATING TEMPERATURE, case
98
108
45
±Vs−8
−Vs+7
+Vs−2
-Vs−2.8
10
± 15
Full temperature range, f ≥ 60Hz
Full temperature range
−40
106
10
+VB−15
−VB+7
± 75
UNITS
mV
μV/OC
μV/V
pA
pA/V
pA
GΩ
pF
V
V
dB
μV RMS
dB
MHz
degree
2
60
+Vs−6.6
−Vs+6
+Vs−1.2
+Vs+2.2
10
12
2.5
4
200C
175°C
−40 to 105°C
−40 to 105°C
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
INPUT
ABSOLUTE MAXIMUM RATINGS
200V
±Vs ±20V
25A
125W
± 20V
±VB
V
V
11
± 100
22
26
0.9
1.2
105
A
V/μS
μS
Ω
V
mA
mA
O
C/W
C/W
O
C
O
NOTES:
1. Unless otherwise noted: TC = 25OC, compensation Cc = 470pF, DC input specifications are ± value given, power supply voltage is typical rating.
2. Derate internal power dissipation to achieve high MTBF.
3. Doubles for every 10OC of case temperature increase.
4. +Vs and −Vs denote the positive and negative supply voltages to the output stage. +VB and −VB denote the positive and negative supply voltages to the
input stages.
5. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
7. Power supply voltages +VB and −VB must not be less than +Vs and −Vs respectively. Total voltage +VB to −VB 240V maximum.
8. The PAD38 is constructed with MOSFET transistors and ESD handling procedures must be observed.
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
3
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
PAD38
OPERATING CONSIDERATIONS
POWER OPERATIONAL AMPLIFIER
SAFETY FIRST
CURRENT LIMIT
The current limiting function of the PAD38 is a versatile
circuit that can be used to implement a four-wire current limit
configuration. The four-wire current limit configuration insures
that parasitic resistance in the output line, Rp, does not affect
the programmed current limit setting. See Figure 1 below. The
sense voltage for current limit is 0.7V. Thus:
0.7V
IL =
RS
Where IL is the value of the limited current and RS is the
value of the current limit sense resistor.
In addition, the sense voltage has a temperature coefficient
approximately equal to –2.2mV/oC.
RF
IN
RIN
30
24
23
+ILIM
-ILIM
PAD38
29
OUT RP
15-17
RS
RL
PHASE COMPENSATION
The PAD38 must be phase compensated. The
compensation capacitor, CC, is connected between pins 4
and 6. The compensation capacitor must be an NPO type
capacitor rated for the full supply voltage (200V). On page
2, under Amplifier Pinout and Connections, you will find a
table that gives recommended compensation capacitance
value for various circuit gains and the resulting slew rate for
each capacitor value. Consult also the small signal response
and phase response plots for the selected compensation
value in the Typical Performance Graphs section. A
compensation capacitor less than 100pF is not
recommended.
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
The operating voltages of the PAD38 are potentially deadly.
When developing an application circuit it is wise to begin with
power supply voltages as low as possible while checking for
circuit functionality. Increase supply voltages slowly as
confidence in the application circuit increases. Always use a
“hands off” method whereby test equipment probes are
attached only when power is off.
USING THE IQ PIN FUNCTION
When pin 25 (IQ) is tied to pin 6 (Cc1) the class AB bias of
the output stage becomes C bias. The quiescent current of
the PAD38 typically drops by 10mA. In some applications
the reduced quiescent current is important. However, note
that applying this option will raise the output impedance of
the amplifier which may change the stability of the circuit
and will increase crossover distortion also.
BOOST OPERATION
The small signal stages of the PAD38 are connected to the
±VB power supply pins. When the ±VB voltages are greater
than the ±Vs power supply pins the small signal stages of
the amplifier are biased so that the output transistors can be
driven very close to the ±Vs rails. Close swings to the
supply rails increase the efficiency of the amplifier and
make better use the supply voltages. This technique is often
used to operate the amplifier with only a single high current
power supply, thus reducing the system size and cost. Also
see the application article AN-22 Single Supply Operation
with Power Op Amps for more detailed information and
circuits.
Figure 1
MOUNTING THE AMPLIFIER
In most applications the amplifier must be attached to a heat
sink. Spread a thin and even coat of heat sink grease across the
back of the PAD38 and also the heat sink where the amplifier is
to be mounted. Push the amplifier into the heat sink grease on
the heat sink while slightly twisting the amplifier back and
forth a few times to bed the amplifier into the heat sink grease.
On the final twist align the mounting holes of the amplifier
with the mounting holes in the heat sink and finish the
mounting using 4-40 hex male-female spacers. Mount the
amplifier to the mother board with 4-40 X 1/4” screws.
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
4
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
POWER OPERATIONAL AMPLIFIER
POWER DERATING
NORMALIZED QUIESCENT CURRENT, IQ (%)
120
100
80
60
40
20
-40
-20
0
20
40
60
80 100
CASE TEMPERATURE, TC (OC)
NORMALIZED QUIESCENT CURRENT, IQ(%)
1.5
1.2
0.9
0.6
0.3
0
-0.3
-0.6
-0.9
-40
0
20
40
60
CASE TEMP, OC
80
100
90
80
70
60
50
120
0
40
80
120
160
TOTAL SUPPLY VOLTAGE, (V)
200
QUIESCENT CURRENT VS TEMPERATURE
120
110
100
90
-40
-20
0
20
40
60
80
CASE TEMPERATURE, OC
100
120
HARMONIC DISTORTION
11
S
-VB=-V
4
3
TJ=25OC
2
0.1
Av = -10
Cc = 100pF
8Ω LOAD
±Vs = ±38V
5W
PUT
-OUT
50
W
+VB=+VS
+OUTPUT,
5
0.01
-10V
B=-VS
UT, -V
-OUTP
1
0
100
OUTPUT SWING FROM SUPPLY RAILS
6
OUTPUT SWING FROM +Vs OR -Vs, V
-20
DISTORTION, %
OFFSET VOLTAGE,Vos (mV)
1.8
QUIESCENT CURRENT VS SUPPLY VOLTAGE
110
120
OFFSET VOLTAGE DRIFT
2.1
120
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
TOTAL POWER DISSIPATION, PD (W)
140
0
PAD38
TYPICAL PERFORMANCE GRAPHS
+VB=+V
+OUTPUT,
0
2
4
6
OUTPUT AMPS, A
8
S+10V
10
0.001
0.001
30
100
1k
1000
FREQUENCY, F(Hz)
10k
10000
30k
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
5
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
POWER OPERATIONAL AMPLIFIER
PAD38
TYPICAL PERFORMANCE GRAPHS
SMALL SIGNAL RESPONSE
120
-90
-100
60
C
c=
22
0p
F
F
0p
47
c=
C
40
C
c=
47
pF
Cc
-120
0p
F
C
c=
-130
C
-140
22
c=
Cc
=4
-150
20
=4
7
0p
F
10
7p
F
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
F
0p
10
PHASE, Θ(O)
80
0p
F
-160
0
8Ω LOAD
IO=500mA DC
1
200
40
30
1k 10000
10k 100000
100 1000
100k 1000000
1M 3M
FREQUENCY, F(Hz)
-180
30k
1M
100k
100000
1000000
FREQUENCY, F(Hz)
3M
POWER RESPONSE
F
47p
C C=
pF
100
C C=
pF
220
C C=
100
90
80
70
60
50
10
10
-170
pF
470
C C=
OUTPUT VOLTAGE SWING, V(p-p)
-110
c=
C
OPEN LOOP GAIN, A(dB)
100
-20
SMALL SIGNAL PHASE RESPONSE
20
10
1000
1k
100k
10000
100000
10k
FREQUENCY, F(Hz)
1000000
1M
1kHz sine clipped by current limit into 100Ω load
10kHz square into 8Ω load, G= −10,CC=100pF, Vs=±50V
30kHz sine into 8Ω load, G= −10,CC=100pF, Vs=±50V
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
6
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
PAD38
POWER OPERATIONAL AMPLIFIER
30
SAFE OPERATING AREA
SAFE OPERATING AREA
OUTPUT CURRENT, Io (A)
10
25 O
C
PowerAmp Design ΠPAD38 ΠPOWER OPERATIONAL AMPLIFIER
1m
S
10
m
S
85 O
C
12
5O
C
1
PULSE 3% DUTY CYCLE
0.1
1
10
100 200
SUPPLY TO OUTPUT DIFFERENTIAL,Vs-Vo (V)
SAFE OPERATING AREA
Power Amp Design Π3381 W Vision Dr ΠTucson AZ 85742 ΠUSA ΠPhone (520)579-3441 ΠFax (208)279-5458 ΠWeb Site: www.PowerAmpDesign.net
7
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland
POWER OPERATIONAL AMPLIFIER
PAD38
DIMENSIONAL INFORMATION
14
1
PowerAmp Design  PAD38  POWER OPERATIONAL AMPLIFIER
30
15
Power Amp Design  3381 W Vision Dr  Tucson AZ 85742  USA  Phone (520)579-3441  Fax (208)279-5458  Web Site: www.PowerAmpDesign.net
8
European Stocking Distributor
Phone: +41 44 730 33 53 / Em‌ai‌l: sa‌le‌s‌@‌cond‌atas‌.‌c‌o‌m / w‌w‌w‌.co‌ndatas‌.c‌o‌m
Rietbachstrasse 7, 8952 Schlieren (ZH) Switzerland