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FEATURES
• LOW BIAS CURRENT, LOW NOISE — FET Input
• FULLY PROTECTED INPUT — Up to ±150V
• WIDE SUPPLY RANGE — ±15V to ±150V
APPLICATIONS
• HIGH VOLTAGE INSTRUMENTATION
• ELECTROSTATIC TRANSDUCERS & DEFLECTION
• PROGRAMMABLE POWER SUPPLIES UP TO 290V
• ANALOG SIMULATORS
DESCRIPTION
The PA83 is a high voltage operational amplifier designed
for output voltage swings up to ±145V with a dual (±) supply or
290V with a single supply. Its input stage is protected against
transient and steady state overvoltages up to and including
the supply rails. High accuracy is achieved with a cascode
input circuit configuration. All internal biasing is referenced
to a zener diode fed by a FET constant current source. As
a result, the PA83 features an unprecedented supply range
and excellent supply rejection. The output stage is biased in
the class A/B mode for linear operation. Internal phase com-
pensation assures stability at all gain settings without need
for external components. Fixed current limits protect these
amplifiers against shorts to common at supply voltages up to
120V. For operation into inductive loads, two external flyback
pulse protection diodes are recommended. However, a heatsink
may be necessary to maintain the proper case temperature
under normal operating conditions.
This hybrid circuit utilizes beryllia (BeO) substrates, thick
(cermet) film resistors, ceramic capacitors and silicon semicon-
ductor chips to maximize reliability, minimize size and give top
performance. Ultrasonically bonded aluminum wires provide
reliable interconnections at all operating temperatures. The
8-pin TO-3 package is hermetically sealed and electrically iso-
lated. The use of compressible thermal isolation washers and/or
improper mounting torque voids product warranty. Please see
Application Note 1 “General Operating Considerations”.
EXTERNAL CONNECTIONS
TYPICAL APPLICATION
While piezo electric transducers present a complex imped-
ance, they are often primarily capacitive at useful frequen-
cies. Due to this capacitance, the speed limitation for a given
transducer/amplifier combination may well stem from limited
current drive rather than power bandwidth restrictions. With
its drive capability of 75mA, the PA83 can drive transducers
having up to 2nF of capacitance at 40kHz at maximum output
voltage. In the event the transducer may be subject to shock
or vibration, flyback diodes, voltage clamps or other protection
networks must be added to protect the amplifier from high
voltages which may be generated.
EQUIVALENT SCHEMATIC
8-PIN TO-3
PACKAGE STYLE CE
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ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, +VS to –VS 300V
OUTPUT CURRENT, within SOA Internally Limited
POWER DISSIPATION, internal at TC = 25°C1 17.5W
INPUT VOLTAGE, differential ±300V
INPUT VOLTAGE, common mode ±300V
TEMPERATURE, pin solder - 10s max (solder) 300°C
TEMPERATURE, junction 175°C
TEMPERATURE RANGE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C
PA83 PA83A
PARAMETER TEST CONDITIONS 2 MIN TYP MAX MIN TYP MAX UNITS
INPUT
OFFSET VOLTAGE, initial TC = 25°C ±1.5 ±3 ±.5 ±1 mV
OFFSET VOLTAGE, vs. temperature Full temperature range ±10 ±25 ±5 ±10 µV/°C
OFFSET VOLTAGE, vs. supply TC = 25°C ±.5 ±.2 µV/V
OFFSET VOLTAGE, vs. time TC = 25°C ±75 * µV/√kh
BIAS CURRENT, initial3 TC = 25°C 5 50 3 10 pA
BIAS CURRENT, vs. supply TC = 25°C .01 * pA/V
OFFSET CURRENT, initial3 TC = 25°C ±2.5 ±50 ±1.5 ±10 pA
OFFSET CURRENT, vs. supply TC = 25°C ±.01 * pA/V
INPUT IMPEDANCE, DC TC = 25°C 1011 * Ω
INPUT CAPACITANCE Full temperature range 6 * pF
COMMON MODE VOLTAGE RANGE4 Full temperature range ±VS–10 * V
COMMON MODE REJECTION, DC Full temperature range 130 * dB
GAIN
OPEN LOOP GAIN at 10Hz TC = 25°C, RL = 2KΩ 96 116 * * dB
UNITY GAIN CROSSOVER FREQ. TC = 25°C, RL = 2KΩ 5 3 * MHz
POWER BANDWIDTH TC = 25°C, RL = 10KΩ 60 40 * kHz
PHASE MARGIN Full temperature range 60 * °
OUTPUT
VOLTAGE SWING4, full load Full temp. range, IO = 75mA ±VS–10 ±VS–5 * * V
VOLTAGE SWING4 Full temp. range, IO = 15mA ±VS–5 ±VS–3 * * V
CURRENT, peak TC = 25°C 75 * mA
CURRENT, short circuit TC = 25°C 100 * mA
SLEW RATE6 TC = 25°C, RL = 2KΩ 20 30 * * V/µs
CAPACITIVE LOAD, unity gain Full temperature range 10 * nF
CAPACITIVE LOAD, gain > 4 Full temperature range SOA * µF
SETTLING TIME to .1% TC = 25°C, RL = 2KΩ, 10V step 12 * µs
POWER SUPPLY
VOLTAGE TC = –55°C to +125°C ±15 ±150 ±150 * * * V
CURRENT, quiescent TC = 25°C 6 8.5 * * mA
THERMAL
RESISTANCE, AC, junction to case5 F > 60Hz 4.26 * °C/W
RESISTANCE, DC, junction to case F < 60Hz 6.22 8.57 * * °C/W
RESISTANCE, case to air 30 * °C/W
TEMP. RANGE, case (PA83/PA83A) Meets full range specification –25 +85 * * °C
PA83 • PA83A
NOTES: * The specification of PA83A is identical to the specification for PA83 in applicable column to the left.
1. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF.
2. The power supply voltage for all tests is the TYP rating, unless otherwise noted as a test condition.
3. Doubles for every 10°C of temperature increase.
4. +VS and –VS denote the positive and negative supply rail respectively. Total VS is measured from +VS to –VS.
5. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
6. Signal slew rates at pins 5 and 6 must be limited to less than 1V/ns to avoid damage. When faster waveforms are unavoidable,
resistors in series with those pins, limiting current to 150mA will protect the amplifier from damage.
The internal substrate contains beryllia (BeO). Do not break the seal. If accidentally broken, do not crush, machine, or
subject to temperatures in excess of 850°C to avoid generating toxic fumes.
CAUTION
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TYPICAL PERFORMANCE
GRAPHS PA83 • PA83A
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
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OPERATING
CONSIDERATIONS
PA83 • PA83A
GENERAL
Please read Application Note 1 "General Operating Con-
siderations" which covers stability, supplies, heat sinking,
mounting, current limit, SOA interpretation, and specification
interpretation. Visit www.apexmicrotech.com for design tools
that help automate tasks such as calculations for stability, in-
ternal power dissipation, current limit and heat sink selection.
The "Application Notes" and "Technical Seminar" sections
contain a wealth of information on specific types of applications.
Package outlines, heat sinks, mounting hardware and other
accessories are located in the "Packages and Accessories"
section. Evaluation Kits are available for most Apex product
models, consult the "Evaluation Kit" section for details. For
the most current version of all Apex product data sheets, visit
www.apexmicrotech.com.
SAFE OPERATING AREA (SOA)
The bipolar output stage of this high voltage amplifier has
two distinct limitations.
1. The internal current limit, which limits maximum available
output current.
2. The second breakdown effect, which occurs whenever the
simultaneous collector current and collector-emitter voltage
exceed specified limits.
The SOA curves combine the effect of these limits. For a
given application, the direction and magnitude of the output
current should be calculated or measured and checked against
the SOA curves. This is simple for resistive loads but more
complex for reactive and EMF generating loads. However, the
following guidelines may save extensive analytical efforts:
This data sheet has been carefully checked and is believed to be reliable, however, no responsibility is assumed for possible inaccuracies or omissions. All specifications are subject to change without notice.
PA83U REV O NONEMBER 2004 © 2004 Apex Microtechnology Corp.
1. The following capacitive and inductive loads are safe:
±VS C(MAX) L(MAX)
150V .7 F 1.5H
125V 2.0µF 2.5H
100V 5.µF 6.0H
75V 60µF 30H
50V ALL ALL
2. Short circuits to ground are safe with dual supplies up to
120V or single supplies up to 120V.
3. Short circuits to the supply rails are safe with total supply
voltages up to 120V, e.g. ±60V.
4. The output stage is protected against transient flyback.
However, for protection against sustained, high energy
flyback, external fast-recovery diodes should be used.
INDUCTIVE LOADS
Two external diodes as shown in Figure 1, are required
to protect these amplifiers against flyback (kickback) pulses
exceeding the supply voltages of the amplifier when driving
inductive loads. For component selection, these external diodes
must be very quick, such as ultra fast recovery diodes with
no more than 200 nanoseconds of reverse recovery time. Be
sure the diode voltage rating is greater than the total of both
supplies. The diode will turn on to divert the flyback energy
into the supply rails thus protecting the output transistors from
destruction due to reverse bias.
A note of caution about the supply. The energy of the flyback
pulse must be absorbed by the power supply. As a result, a tran-
sient will be superimposed on the supply voltage, the magnitude
of the transient being a function of its transient impedance and
current sinking capability. If the supply voltage plus transient
exceeds the maximum supply rating or if the AC impedance
of the supply is unknown, it is best to clamp the output and the
supply with a zener diode to absorb the transient.
