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FEATURES
• HIGH SLEW RATE — 200V/µs
• FAST SETTLING TIME — .1% in 1µs (PA84S)
• FULLY PROTECTED INPUT — Up to ±150v
• LOW BIAS CURRENT, LOW NOISE — FET Input
• WIDE SUPPLY RANGE — ±15V to ±150V
APPLICATIONS
• HIGH VOLTAGE INSTRUMENTATION
• ELECTROSTATIC TRANSDUCERS & DEFLECTION
• PROGRAMMABLE POWER SUPPLIES UP TO 290V
• ANALOG SIMULATORS
DESCRIPTION
The PA84 is a high voltage operational amplifier designed
for output voltage swings up to ±145V with a dual supply or
290V with a single supply. Two versions are available. The
new PA84S, fast settling amplifier can absorb differential input
overvoltages up to ±50V while the established PA84 and PA84A
can handle differential input overvoltages of up to ±300V. Both
versions are protected against common mode transients and
overvoltages up to 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 PA84 features an unprecedented sup-
ply range and excellent supply rejection. The output stage is
biased-on for linear operation. External phase compensation
allows for user flexibility in obtaining the maximum slew rate.
Fixed current limits protect these amplifiers against shorts to
common at supply voltages up to 150V. 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 integrated circuit utilizes a beryllia (BeO) sub-
strate, thick film resistors, ceramic capacitors and semiconduc-
tor 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
isolated. The use of compressible thermal isolation washers
and/or improper mounting torque will void the product warranty.
Please see “General Operating Considerations”.
EXTERNAL CONNECTION
TYPICAL APPLICATION
The PA84 is ideally suited to driving ink jet control units (of-
ten a piezo electric device) which require precise pulse shape
control to deposit crisp clear date or lot code information on
product containers. The external compensation network has
been optimized to match the gain setting of the circuit and the
complex impedance of the ink jet control unit. The combination
of speed and high voltage capabilities of the PA84 form ink
droplets of uniform volume at high production rates to enhance
the value of the printer.
EQUIVALENT SCHEMATIC
*Not included in PA84S.
8-PIN TO-3
PACKAGE STYLE CE
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
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NOTES: * The specification of PA84A is identical to the specification for PA84/PA84S in applicable column to the left.
1. 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.
2. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF.
3. The power supply voltage for all tests is ±150V, unless otherwise noted as a test condition.
4. Doubles for every 10°C of temperature increase.
5. +VS and –VS denote the positive and negative power supply rail respectively.
6. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, +VS to –VS 300V
OUTPUT CURRENT, within SOA Internally Limited
POWER DISSIPATION, internal at TC = 25°C2 17.5W
INPUT VOLTAGE, differential PA84/PA84A1 ±300V
INPUT VOLTAGE, differential PA84S ±50V
INPUT VOLTAGE, common mode1 ±VS
TEMPERATURE, pins for 10s max (solder) 300°C
TEMPERATURE, junction2 175°C
TEMPERATURE RANGE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C
PA84 • PA84A • PA84S
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
PA84/PA84S PA84A
PARAMETER TEST CONDITIONS 3 MIN TYP MAX MIN TYP MAX UNITS
INPUT
OFFSET VOLTAGE, initial TC = 25°C ±1.5 ±3 ±.5 ±1 mV
OFFSET VOLTAGE, vs. temperature TC = –25° to +85°C ±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, initial4 TC = 25°C 5 50 3 10 pA
BIAS CURRENT, vs. supply TC = 25°C .01 * pA/V
OFFSET CURRENT, initial4 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 TC = –25° to +85°C 6 * pF
COMMON MODE VOLTAGE RANGE5 TC = –25° to +85°C ±VS–10 ±VS–8.5 * * V
COMMON MODE REJECTION, DC TC = –25° to +85°C 130 * dB
GAIN
OPEN LOOP GAIN at 10Hz TC = 25°C, RL = ∞ 120 * dB
OPEN LOOP GAIN at 10Hz. TC = 25°C, RL = 3.5KΩ 100 118 * * dB
GAIN BANDWIDTH PRODUCT@ 1MHz TC = 25°C, RL = 3.5KΩ, RC = 20KΩ 75 * MHz
POWER BANDWIDTH, high gain TC = 25°C, RL = 3.5KΩ, RC = 20KΩ 250 180 * kHz
POWER BANDWIDTH, low gain TC = 25°C, RL = 3.5KΩ, RC = 20KΩ 120 * kHz
OUTPUT
VOLTAGE SWING5 TC = 25°C, IO = ±40mA ±VS–7 ±VS–3 * * V
VOLTAGE SWING5 TC = –25° to +85°C, IO = ±15mA ±VS–5 ±VS–2 * * V
CURRENT, peak TC = 25°C 40 * mA
CURRENT, short circuit TC = 25°C 50 * mA
SLEW RATE, high gain TC = 25°C, RL = 3.5KΩ, RC = 20KΩ 200 150 * V/µs
SLEW RATE, low gain TC = 25°C, RL = 3.5KΩ, RC = 2KΩ 125 * V/µs
SETTLING TIME .01% at gain = 100 TC = 25°C, RL = 3.5KΩ PA84S 2 µs
SETTLING TIME .1% at gain = 100 RC = 20KΩ, VIN = 2V step ONLY 1 µs
SETTLING TIME .01% at gain = 100 TC = 25°C, RL = 3.5KΩ PA84/84A 20 20 µs
SETTLING TIME .1% at gain = 100 RC = 20KΩ, VIN = 2V step 12 12 µs
POWER SUPPLY
VOLTAGE TC = –55°C to +125°C ±15 ±150 * * V
CURRENT, quiescent TC = 25°C 5.5 7.5 * * mA
THERMAL
RESISTANCE, AC, junction to case6 TC = –55°C to +125°C, F > 60Hz 4.26 * °C/W
RESISTANCE, DC, junction to case TC = –55°C to +125°C, F < 60Hz 6.22 8.57 * * °C/W
RESISTANCE, case to air TC = –55°C to +125°C 30 * °C/W
TEMPERATURE RANGE, case Meets full range specifications –25 +85 * * °C
SPECIFICATIONS
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TYPICAL PERFORMANCE
GRAPHS PA84 • PA84A • PA84S
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
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OPERATING
CONSIDERATIONS
PA84 • PA84A • PA84S
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 operational
amplifier has two output 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
exceeds 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:
1. The following capacitive and inductive loads are safe:
±VS C(MAX) L(MAX)
150V 1.2µF .7H
125V 6.0µF 25H
100V 12µF 90H
75V ALL ALL
2. Short circuits to ground are safe with dual supplies up to
±150V or single supplies up to 150V.
3. Short circuits to the supply rails are safe with total supply
voltages up to 150V (i.e. ±75V).
OUTPUT PROTECTION
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.
STABILITY
Due to its large bandwidth the PA84 is more likely to oscil-
late than lower bandwidth Power Operational Amplifiers such
as the PA83 or PA08. To prevent oscillations, a reasonable
phase margin must be maintained by:
1. Selection of the proper phase compensation capacitor and
resistor. Use the values given in the table under external
connections and interpolate if necessary. The phase margin
can be increased by using a large capacitor and a smaller
resistor than the slew rate optimized values listed in the
table. The compensation capacitor may be connected to
common (in lieu of +VS) if the positive supply is properly
bypassed to common. Because the voltage at pin 8 is only a
few volts below the positive supply, this ground connection
requires the use of a high voltage capacitor.
2. Keeping the external sumpoint stray capacitance to ground
at a minimum and the sumpoint load resistance (input and
feedback resistors in parallel) below 500Ω. Larger sumpoint
load resistance can be used with increased phase compen-
sation (see 1 above).
3. Connecting the amplifier case to a local AC common thus
preventing it from acting as an antenna.
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.
PA84U REV N NOVEMBER 2004 © 2004 Apex Microtechnology Corp.
