PA78
Power Operational Amplifier
RoHS
COMPLIANT
FEATURES
•
•
•
•
•
•
•
•
A Unique (Patent Pending) Technique for Very Low Quiescent Current
Over 350 V/µs Slew Rate
Wide Supply Voltage
Single Supply: 20V To 350V
Split Supplies: ± 10V To ± 175V
Output Current – 150mA Cont.; 200mA Pk
Up to 14 Watt Dissipation Capability
Over 200 kHz Power Bandwidth
APPLICATIONS
•
•
•
•
Piezoelectric Positioning And Actuation
Electrostatic Deflection
Deformable Mirror Actuators
Chemical And Biological Stimulators
DESCRIPTION
The PA78 is a high voltage, high speed, low idle current op-amp capable of delivering up to 200mA peak
output current. Due to the dynamic biasing of the input stage, it can achieve slew rates over 350V/µs, while
only consuming less than 1mA of idle current. External phase compensation allows great flexibility for the
user to optimize bandwidth and stability.
The output stage is protected with user selected current limit resistor. For the selection of this current
limiting resistor, pay close attention to the SOA. Proper heatsinking is required for maximum reliability.
BLOCK DIAGRAM
Figure 1: Block Diagram
VOUT+
ACTIVE LOAD
BUFFER
V+
V–
CLASS AB INPUT STAGE
ACTIVE LOAD
www.apexanalog.com
VOUT–
CURRENT
LIMIT
© Apex Microtechnology Inc.
All rights reserved
VOUT
Feb 2023
PA78U Rev F
PA78
TYPICAL CONNECTION
Figure 2: Typical Connection
2
PA78U Rev F
PA78
PINOUT AND DESCRIPTION TABLE
Figure 3: External Connections
1
2
-IN
+IN
3 -RC
4 +RC
5 +CC
6 NC
7 NC
8 NC
9
NC
10 NC
TOP
VIEW
-VS 20
19
-CC
18
VOUT
CL 17
+VS 16
15
NC
NC 14
13
NC
12
NC
11
NC
Pin Number
Name
Description
1
2
-IN
+IN
3
-RC
4
+RC
5
+CC
16
+Vs
17
CL
The inverting input.
The non-inverting input.
Negative compensation resistor connection. Select value based on Phase Compensation. See applicable section.
Positive compensation resistor connection. Select value based on Phase Compensation. See applicable section.
Positive compensation capacitor connection. Select value based on Phase Compensation. See applicable section.
The positive supply rail.
Connect to the current limit resistor. Output current flows into/out of this pin
through RCL. The output pin and the load are connected to the other side of RCL.
18
OUT
19
-CC
20
All Others
-Vs
NC
PA78U Rev F
The output. Connect this pin to load and to the feedback resistors.
Negative compensation capacitor connection. Select value based on Phase Compensation. See applicable section.
The negative supply rail.
No connection.
3
PA78
SPECIFICATIONS
Unless otherwise noted: TC = 25°C, DC input specifications are ± value given, power supply voltage is typical
rating.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Max
Units
+Vs to -Vs
350
V
Output Current, peak (200ms), within SOA
IO
200
mA
Power Dissipation, internal, DC
PD
14
W
Supply Voltage, total
Input Voltage, differential
Input Voltage, common mode
Min
VIN (Diff)
-15
16
V
Vcm
-VS
+VS
V
150
°C
-55
125
°C
-40
125
°C
Temperature, junction 1
Temperature Range, storage
TJ
Operating Temperature, case
TC
1. Long term operation at the maximum junction temperature will result in reduced product life. Derate power dissipation
to achieve high MTTF.
INPUT
Parameter
Offset Voltage, initial
Offset Voltage vs. Temperature
Offset Voltage vs. Supply
Bias Current, initial
Offset Current, initial
Test Conditions
Min
Typ
Max
Units
-40
8
-63
40
mV
µV/°C
µV/V
pA
pA
0 to 125°C (Case Temp)
8.5
12
Input Resistance, DC
Common Mode Voltage Range,
Neg.
Common Mode Voltage Range,
Pos.
Common Mode Rejection, DC
Noise
Noise, VO Noise
4
90
700 kHz
32
200
400
108
Ω
+VS - 2
V
-VS + 5.5
V
118
418
dB
µV RMS
500
nV/√Hz
PA78U Rev F
PA78
GAIN
Parameter
Test Conditions
Open Loop @ 1Hz
Gain Bandwidth Product @ 1MHz
Phase Margin
Full temp range
+VS = 160V, −VS = -160V
Power Bandwidth, 300VP-P
Min
Typ
Max
Units
89
120
1
50
dB
MHz
°
200
kHz
OUTPUT
Parameter
Test Conditions
Min
Typ
Voltage Swing
IO = 10mA
|VS| - 2
Voltage Swing
IO = 100mA
|VS| - 8.6
Voltage Swing
IO = 150mA
|VS| - 10
Current, continuous, DC
Slew Rate
Settling Time, to 0.1%
Output Resistance, No load
Max
V
|VS| - 12
100
V
V
150
Package Tab connected to
GND
2V Step
RCL = 6.2 Ω
Units
mA
350
V/µs
1
µs
44
Ω
POWER SUPPLY
Parameter
Test Conditions
Voltage
Current, quiescent
1
±150V Supply
Min
Typ
Max
Units
±10
±150
±175
V
0.2
0.7
2.5
mA
Min
Typ
Max
Units
9.1
°C/W
1. Supply current increases with signal frequency. See graph on page 4.
THERMAL
Parameter
Test Conditions
Resistance, DC, junction to case
Full temp range
8.3
Resistance, DC, junction to air 1
Full temp range
25
°C/W
Resistance, DC, junction to air 2
Temperature Range, case
Full temp range
19.1
°C/W
-40
125
°C
1. Rating applies when the heatslug of the DK package is soldered to a minimum of 1 square inch foil area of a printed circuit board.
2. Rating applies with the JEDEC conditions outlined in the Heatsinksing section of this datasheet.
PA78U Rev F
5
PA78
TYPICAL PERFORMANCE GRAPHS
Figure 4: Power Derating
Figure 5: Current Limit
160
140
20
Current Limit, ILIM (mA)
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25
15
10
5
120
100
80
60
+VS
40
–VS
20
0
0
0
25
50
75
100
125
0
Figure 6: Common Mode Rejection
Figure 7: Power Supply Rejection
100
120
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140
100
80
60
40
20
0
10
100
1k
Frequency, F (Hz)
6
100
Resistor Value (ɏ)
Case Temperature, TC (°C)
1
50
10k
100k
-VS
80
+VS
60
40
20
0
100
1k
10k
Frequency, F (Hz)
PA78U Rev F
PA78
Figure 8: Small Signal Open Loop Gain
Figure 9: Small Signal Open Loop Phase
100
180
RC = Open, CC = 0pF
150
RC = 3.3 k, CC = 1pF
80
120
RC = 3.3 k, CC = 2.2pF
RC = 3.3 k, CC = 5pF
40
20 CS = 68pF
PIN = -40dBm
RC = 3.3 k, CC = 10pF
R
0 BIAS = Open
RSсϰϴ͘ϳё
RC = 3.3 k, CC = 22pF
VS = ±50V
-20
1k
10k
100k
60
30
1M
Figure 11: Small Signal Open Loop Phase,
VO= 250 mVP-P
180
45
35
150
25
120
A V = +26
C = 5pF
R
-5 BIAS = 100 k C
RC = 3.3 k
CC = 10pF
-15 RF = 35.7 k
RG = 1.5 k
CC = 22pF
-25 RL = 50 k
VS = ±50V
-35
10k
100k
1M
Frequency (Hz)
RC = 3.3 k, CC = 22pF
RC = 3.3 k, CC = 10pF
90
CC = 1pF
CC = 2.2pF
Phase (°)
Gain (dB)
CC = 0pF
PA78U Rev F
1M
Frequency (Hz)
Figure 10: Small Signal Gain vs.
Compensation VO= 500 mVP-P
5
RC = 3.3 k, CC = 5pF
RC = 3.3 k, CC = 2.2pF
0 CS = 68pF
PIN = -40dBm
RC = 3.3 k, CC = 1pF
-30 RBIAS = 100K
RSсϰϴ͘ϳё
RC = Open, CC = 0pF
-60
VS = ±50V
-90
1k
10k
100k
Frequency (Hz)
15
RC = 3.3 k, CC = 22pF
90
Phase (°)
Gain (dB)
60
RC = 3.3 k, CC = 10pF
10M
60
30
RC = 3.3 k, CC = 5pF
RC = 3.3 k,
0
CS = 68pF
CC = 2.2pF
-30 P = -40dBm
IN
RC = 3.3 k, CC = 1pF
-60 RBIAS = Open
RSсϰϴ͘ϳё
RC = Open, CC = 0pF
-90
1k
10k
100k
1M
Frequency (Hz)
7
PA78
Figure 12: Small Signal Gain vs.
Compensation, VO= 5 VP-P
Figure 13: Large Signal Gain vs.
Compensation, VO= 50VP-P
35
35
CC = 0pF
CC = 0pF
25
25
15
5
CC = 1pF
Gain (dB)
Gain (dB)
15
CC = 2.2pF
-5
A V = +26 CC = 5pF
RBIAS = 100 k
CC = 10pF
-15 R = 35.7 k
F
RG = 1.5 k
CC = 22pF
-25 R = 50 k
L
VS = ±50V
-35
10k
100k
1M
CC = 1pF
5
CC = 2.2pF
-5
A V = +26
RBIAS = 100 k
RF = 35.7 k
RG = 1.5 k
RL = 50 k
VS = ±50V
-15
-25
-35
10k
10M
Voltage Drop From Supply (V)
Gain (dB)
500 mVP-P
15
-25
10k
A V = +51
RBIAS = 100 k
RC = OPEN
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±50V
5 VP-P
100k
50 VP-P
10
-VS SIDE DROP
8
6
+VS SIDE DROP
4
2
0
1M
Frequency (Hz)
8
10M
12
35
-15
1M
Figure 15: Output Voltage Swing
45
-5
CC = 22pF
Frequency (Hz)
Figure 14: Gain vs. Input/Output
Signal Level
5
CC = 10pF
100k
Frequency (Hz)
25
CC = 5pF
10M
0
50
100
150
200
Peak to Peak Load Current (mA)
PA78U Rev F
PA78
Figure 16: Power Response
Figure 17: SR+/SR- (25% - 75%)
1000
350
SR+
GAIN = -50
800
SR-
GAIN = -100
250
SR (V/μs)
Output Voltage (V)
300
200
150
600
A V = +101
CL = 8pF
RF = 25 k
RGсϮϱϬё
RL = 50 k
VS = ±150V
400
100
200
50
NO COMPENSATION
0
0
1k
10k
100k
0
1M
4
6
8
10
12
14
16
Peak-to-Peak Input Voltage (V)
Frequency, F (Hz)
Figure 18: SR+/SR- (25% - 75%)
Figure 19: SR+/SR- (25% - 75%)
1000
1000
SR+
800
SR600
A V = +51
CL = 8pF
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
400
200
A V = +26
CL = 8pF
RF = 35.6 k
RG = 1.5 k
RL = 50 k
VS = ±150V
800
Slew Rate (V/μs)
Slew Rate (V/μs)
2
600
SR+
400
SR200
0
0
0
2
4
6
8
10
12
14
Peak-to-Peak Input Voltage (V)
PA78U Rev F
16
0
2
4
6
8
10
12
14
16
Peak-to-Peak Input Voltage
9
PA78
Figure 20: SR+/SR- (25% - 75%)
Figure 21: SR+/SR- (25% - 75%)
1600
RF = 75 k
RG = 1.5 k
1000 R = 50 k
L
VS = ±150V
800 CL = 8pF
RF = 75 k
1400 RG = 1.5 k
RL = 50 k
1200 VS = ±150V
CL = 8pF
1000
SR+(A V = -25)
SR-(A V = -25)
SR+(A V = +26)
SR-(A V = +26)
V/μs
600
800
600
400
SR+(A V = -50)
SR-(A V = -50)
SR+(A V = +51)
SR-(A V = +51)
400
200
200
0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Peak-to-Peak Input Voltage (V)
Peak-to-Peak Input Voltage (V)
Figure 22: Transient Response
Figure 23: Transient Response
1.2
30
1.5
10
0.8
20
1
5
0
-5
-10
-15
-4
-2
0
2
input 1
1VP-P
0.4
A V = +26
CC = 2.2pF
CL = 8pF
RC = 3.3 k
RF = 35.7 k
RG = 1.5 k
RL = 50 k
0
4
6
Time (μs)
10
-0.4
-0.8
8
10
-1.2
12
Output Voltage (V)
15
Input Voltage (V)
Output Voltage (V)
0
input 2
2VP-P
10
0
0
A V = +26
CC = 2.2pF
CL = 8pF
RC = 3.3 k
RF = 35.7 k
RG = 1.5 k
RL = 50 k
-10
-20
-30
-4
0.5
-2
0
2
4
6
Input Voltage (V)
SR+/SR- (V/μs)
1200
-0.5
-1
8
10
-1.5
12
Time (μs)
PA78U Rev F
PA78
Figure 24: Transient Response
Figure 25: Rise and Fall Time (10%-90%)
6
50
4
A V = +26
CC = 2.2pF
CL = 8pF
RC = 3.3 k
RF = 35.7 k
RG = 1.5 k
RL = 50 k
0
-50
-100
-2
2
0
4
0
-4
A V = +51
CL = 8pF
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
0.8
0.6
Time (μs)
input 10
10VP-P
Input Voltage (V)
Output Voltage (V)
100
-150
-4
1
8
150
TF
0.4
TR
0.2
-6
6
8
10
0
-8
12
0
Figure 26: Pulse Response vs. CC and RC
60
Out - 1pF
& 3.3 k
0
1.2
0.6
0
-1.2
Out - 5pF & 3.3 k
-90
-1.8
-120
-2.4
0
1
2
3
4
Time (μs)
PA78U Rev F
5
6
7
0.15
1.8
-0.6
-1
12
14
16
A V = +51
CL = 8pF
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
2.4
-30
-150
-2
10
8
-3.0
0.1
IS (A)
input
-60
8
0.2
Input Votlage (V)
Output Votlage (V)
A V = +51
CC = 68pF
CL = 330pF
RCсϰϴё
RF = 75 k
RG = 1.5 k
RL = OPEN
VS = ±150V
Out - 0pF
30
6
Figure 27: Pulse Response
3.0
150
90
4
Peak-to-Peak Input Voltage (V)
Time (μs)
120
2
0.05
0
-0.05
-1
0
1
2
3
4
5
6
Time (μs)
11
PA78
Figure 28: Pulse Response vs. Cap Load
Figure 29: Pulse Response vs. Cap Load
140
140
300pf, 3VP-P
200pf, 3VP-P
100pf, 3VP-P
100
80
80
60
60
Output (v)
Output (v)
100
40
20
A V = -50
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
0
-20
-40
-60
-80
-6
-2
2
6
300pF, 2VP-P
200pF, 2VP-P
100pF, 2VP-P
120
40
20
A V = -50
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
CL = 8pF
0
-20
-40
-60
10 14 18
22 26
-80
-6
30
2
-2
6
Figure 30: Pulse Response vs Cap Load
INPUT
300pF, 1VP-P
200pF, 1VP-P
100pF, 1VP-P
100
Output Votlage (V)
60
40
20
A V = -50
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
0
-20
-40
-60
-2
2
6
10 14 18
Time (μs)
4
200
80
Output (v)
6
300
120
30
Figure 31: Overdrive Recovery
140
12
22 26
Time (μs)
Time (μs)
-80
-6
10 14 18
OUTPUT
100
A V = +51
CC = OPEN
CL = 8pF
RC = OPEN
RF = 75 k
RG = 1.5 k
RL = 50 k
VS = ±150V
0
-100
-200
22 26
30
-300
-4
2
0
-2
Input Votlage (V)
120
-4
-6
-2
0
2
4
6
8
10
12
Time (μs)
PA78U Rev F
PA78
Figure 32: Supply Current vs. VIN
Figure 33: Supply Current vs. Frequency
30
18
A V = +51
CL = 8pF
CS = 68pF
RF = 75 k
RG = 1.5 k
RL = 50 k
RSсϰϴ͘ϳё
VS = ±150V
14
IS (mA)
12
10
8
25
20
IS (mA)
16
15
A V = +51
CL = 8pF
CS = 68pF
RF = 75 k
RG = 1.5 k
RL = 50 k
RSсϰϴ͘ϳё
VS = ±150V
VIN = 6VP
10
6
4
VIN = 3VP
5
2
0
0
1
2
3
4
5
6
7
VIN, VP-P (100kHz sine wave)
PA78U Rev F
8
9
0
10
100
1000
Frequency (kHz Sine Wave)
13
PA78
HEATSINKING AND SAFE OPERATING AREA (SOA)
The MOSFET output stage of the PA78 is not limited by second breakdown considerations as in bipolar
output stages. Only thermal considerations of the package and current handling capabilities limit the Safe
Operating Area. The SOA plots include power dissipation limitations which are dependent upon case temperature. Keep in mind that the dynamic current sources which drive high slew rates can increase the operating temperature of the amplifier during periods of repeated slewing. The plot of supply current vs. input
signal amplitude for a 100 kHz signal provides an indication of the supply current with repeated slewing conditions. This application dependent condition must be considered carefully.
The output stage is self-protected against transient flyback by the parasitic body diodes of the output
stage. However, for protection against sustained high energy flyback, external fast recovery diodes must be
used.
Figure 34: SOA
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20
0m = 2
°C
30
͕d C = 85
͕d C
0.1
KƵƚƉƵƚƵƌƌĞŶƚ&ƌŽŵнVSŽƌͲVS (A)
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10
100
1000
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14
PA78U Rev F
PA78
GENERAL
Please read Application Note 1 “General Operating Considerations” which covers stability, supplies, heat
sinking, mounting, current limit, SOA interpretation, and specification interpretation. Visit www.apexanalog.com for Apex Microtechnology’s complete Application Notes library, Technical Seminar Workbook, and
Evaluation Kits.
TYPICAL APPLICATION
The PA78 is ideally suited for driving continuous drop ink jet printers, in both piezo actuation and deflection applications. The high voltage of the amplifier creates an electrostatic field on the deflection plates to
control the position of the ink droplets. The rate at which droplets can be printed is directly related to the
rate at which the amplifier can drive the plate to a different electrostatic field strength.
Figure 35: Typical Application
THEORY OF OPERATION
The PA78 is designed specifically as a high speed pulse amplifier. In order to achieve high slew rates with
low idle current, the internal design is quite different from traditional voltage feedback amplifiers. Basic op
amp behaviors like high input impedance and high open loop gain still apply. But there are some notable differences, such as signal dependent supply current, bandwidth and output impedance, among others. The
impact of these differences varies depending on application performance requirements and circumstances.
These different behaviors are ideal for some applications but can make designs more challenging in other circumstances.
SUPPLY CURRENT AND BYPASS CAPACITANCE
A traditional voltage feedback amplifier relies on fixed current sources in each stage to drive the parasitic
capacitances of the next stage. These currents combine to define the idle or quiescent current of the amplifier. By design, these fixed currents are often the limiting parameter for slew rate and bandwidth of the
amplifier. Amplifiers which are high voltage and have fast slew rates typically have high idle currents and dissipate notable power with no signal applied to the load. At the heart of the PA78 design is a signal dependent
current source which strikes a new balance between supply current and dynamic performance. With small
PA78U Rev F
15
PA78
input signals, the supply current of the PA78 is very low, idling at less than 1 mA. With large transient input
signals, the supply currents increase dramatically to allow the amplifier stages to respond quickly. The Pulse
Response plot in the typical performance section of this datasheet describes the dynamic nature of the supply current with various input transients.
Choosing proper bypass capacitance requires careful consideration of the dynamic supply currents. High
frequency ceramic capacitors of 0.1µF or more should be placed as close as possible to the amplifier supply
pins. The inductance of the routing from the supply pins to these ceramic capacitors will limit the supply of
peak current during transients, thus reducing the slew rate of the PA78. The high frequency capacitance
should be supplemented by additional bypass capacitance not more than a few centimeters from the amplifier. This additional bypass can be a slower capacitor technology, such as electrolytic, and is necessary to
keep the supplies stable during sustained output currents. Generally, a few microfarads are sufficient.
SMALL SIGNAL PERFORMANCE
The small signal performance plots in the typical performance section of this datasheet describe the
behavior when the dynamic current sources described previously are near the idle state. The selection of
compensation capacitor directly affects the open loop gain and phase performance.
Depending on the configuration of the amplifier, these plots show that the phase margin can diminish to
very low levels when left uncompensated. This is due to the amount of bias current in the input stage when
the part is in standby. An increase in the idle current in the output stage of the amplifier will improve phase
margin for small signals although will increase the overall supply current.
Current can be injected into the output stage by adding a resistor, RBIAS, between CC- and VS+. The size of
RBIAS will depend upon the application but 500µA (50V V+ supply/100K) of added bias current shows significant improvement in the small signal phase plots. Adding this resistor has little to no impact on small signal
gain or large signal performance as under these conditions the current in the input stage is elevated over its
idle value. It should also be noted that connecting a resistor to the upper supply only injects a fixed current
and if the upper supply is fixed and well bypassed. If the application includes variable or adjustable supplies, a
current source diode could also be used. These two terminal components combine a JFET and resistor connected within the package to behave like a current source.
As a second stability measure, the PA78 is externally compensated and performance can be optimized to
the application. Unlike the RBIAS technique, external phase compensation maintains the low idle current but
does affect the large signal response of the amplifier. Refer to the small and large signal response plots as a
guide in making the trade-offs between bandwidth and stability. Due to the unique design of the PA78, two
symmetric compensation networks are required. The compensation capacitor Cc must be rated for a working
voltage of the full operating supply voltage (+VS to –VS). NPO capacitors are recommended to maintain the
desired level of compensation over temperature.
The PA78 requires an external 33pF capacitor between CC- and –VS to prevent oscillations in the falling
edge of the output. This capacitor should be rated for the full supply voltage (+VS to –VS).
LARGE SIGNAL PERFORMANCE
As the amplitude of the input signal increases, the internal dynamic current sources increase the operation bandwidth of the amplifier. This unique performance is apparent in its slew rate, pulse response, and
large signal performance plots. Recall the previous discussion about the relationships between signal amplitude, supply current, and slew rate. As the amplitude of the input amplitude increases from 1VP-P to 15VP-P,
the slew rate increases from 50V/µs to well over 350V/µs.
Notice the knee in the Rise and Fall times plot, at approximately 6VP-P input voltage. Beyond this point
the output becomes clipped by the supply rails and the amplifier is no longer operating in a closed loop fash-
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PA78U Rev F
PA78
ion. The rise and fall times become faster as the dynamic current sources are providing maximum current for
slewing. The result of this amplifier architecture is that it slews fast, but allows good control of overshoot for
large input signals. This can be seen clearly in the large signal Transient Response plots.
CURRENT LIMIT
For proper operation, the current limit resistor, RLIM, must be connected as shown in the external connections diagram. For maximum reliability and protection, the largest resistor value should be used. The minimum practical value for RLIM is about 12Ω. However, refer to the SOA to assist in selecting the optimum
value for RLIM in the intended application. Current limit may not protect against short circuit conditions with
supply voltages over 200V.
LAYOUT CONSIDERATIONS
The PA78 is built on a dielectrically isolated process and the package tab is therefore not electrically connected to the amplifier. For high speed operation, the package tab should be connected to a stable reference
to reduce capacitive coupling between amplifier nodes and the floating tab. It is often convenient to directly
connect the tab to GND or one of the supply rails, but an AC connection through a 1µF capacitor to GND is
also sufficient if a DC connection is undesirable.
Care should be taken to position the RC / CC compensation networks close to the amplifier compensation
pins. Long loops in these paths pick up noise and increase the likelihood of LC interactions and oscillations.
The PA78DK package has a large exposed integrated copper heatslug to which the monolithic amplifier is
directly attached. The solder connection of the heat slug to a 1 square inch foil area on the printed circuit
board will result in improved thermal performance of 25°C/W. In order to improve the thermal performance,
multiple metal layers in the printed circuit board are recommended. This may be adequate heatsinking but
the large number of variables involved suggest temperature measurements be made on the top of the package. Do not allow the temperature to exceed 85°C.
The junction to ambient thermal resistance of the DK package can achieve a 19.1°C/W rating by using the
PCB conditions outlined in JEDEC standard: (JESD51–5):
PCB Conditions:
PCB Layers = 4L, Copper, FR–4
PCB Dimensions = 101.6 x 114.3mm
PCB Thickness = 1.6mm
Conditions:
Power dissipation = 2 Watt
Ambient Temperature = 55°C
ELECTROSTATIC DISCHARGE
Like many high performance MOSFET amplifiers, the PA78 is very sensitive to damage due to electrostatic discharge (ESD). Failure to follow proper ESD handling procedures could have results ranging from
reduced operating performance to catastrophic damage. Minimum proper handling includes the use of
grounded wrist or shoe straps, grounded work surfaces. Ionizers directed at the work in progress can neutralize the charge build up in the work environment and are strongly recommended.
PA78U Rev F
17
PACKAGE OPTIONS
Part Number
Apex Package Style
Description
MSL1
PA78DK
DK
20-pin PSOP
Level 3
1. The Moisture Sensitivity Level rating according to the JEDEC industry standard classification.
PACKAGE STYLE DK
PA78
NEED TECHNICAL HELP? CONTACT APEX SUPPORT!
For all Apex Microtechnology product questions and inquiries, call toll free 800-546-2739 in North America. For
inquiries via email, please contact apex.support@apexanalog.com. International customers can also request
support by contacting their local Apex Microtechnology Sales Representative. To find the one nearest to you,
go to www.apexanalog.com
IMPORTANT NOTICE
Apex Microtechnology, Inc. has made every effort to insure the accuracy of the content contained in this document. However, the information is
subject to change without notice and is provided "AS IS" without warranty of any kind (expressed or implied). Apex Microtechnology reserves the right
to make changes without further notice to any specifications or products mentioned herein to improve reliability. This document is the property of
Apex Microtechnology and by furnishing this information, Apex Microtechnology grants no license, expressed or implied under any patents, mask
work rights, copyrights, trademarks, trade secrets or other intellectual property rights. Apex Microtechnology owns the copyrights associated with the
information contained herein and gives consent for copies to be made of the information only for use within your organization with respect to Apex
Microtechnology integrated circuits or other products of Apex Microtechnology. This consent does not extend to other copying such as copying for
general distribution, advertising or promotional purposes, or for creating any work for resale.
APEX MICROTECHNOLOGY PRODUCTS ARE NOT DESIGNED, AUTHORIZED OR WARRANTED TO BE SUITABLE FOR USE IN PRODUCTS USED FOR LIFE
SUPPORT, AUTOMOTIVE SAFETY, SECURITY DEVICES, OR OTHER CRITICAL APPLICATIONS. PRODUCTS IN SUCH APPLICATIONS ARE UNDERSTOOD TO BE
FULLY AT THE CUSTOMER OR THE CUSTOMER’S RISK.
Apex Microtechnology, Apex and Apex Precision Power are trademarks of Apex Microtechnology, Inc. All other corporate names noted herein may be
trademarks of their respective holders.
PA78U Rev F
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