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FEATURES
• HIGH VOLTAGE — 450V (±225V)
• HIGH SLEW RATE — 1000V/μS
• HIGH OUTPUT CURRENT — 200mA
APPLICATIONS
• HIGH VOLTAGE INSTRUMENTATION
• PIEZO TRANSDUCER EXCITATION
• PROGRAMMABLE POWER SUPPLIES UP TO 430V
• ELECTROSTATIC TRANSDUCERS & DEFLECTION
DESCRIPTION
The PA85 is a high voltage, high power bandwidth MOS-
FET operational amplifier designed for output currents up to
200mA. Output voltages can swing up to ±215V with a dual
supply and up to +440 volts with a single supply. The safe
operating area (SOA) has no second breakdown limitations
and can be observed with all types of loads by choosing an
appropriate current limiting resistor. High accuracy is achieved
with a cascode input circuit configuration. All internal biasing is
referenced to a bootstrapped zener-MOSFET current source.
As a result, the PA85 features an unprecedented supply range
and excellent supply rejection. The MOSFET output stage is
biased on for linear operation. External compensation provides
user flexibility.
This hybrid circuit utilizes thick film (cermet) resistors, ceramic
capacitors and silicon semiconductor chips to maximize reli-
ability, minimize size and give top performance. Ultrasonically
bonded aluminum wires provide reliable interconnections at all
operating temperatures. The 8-pin TO-3 package is hermeti-
cally sealed and electrically isolated. The use of compressible
isolation washers voids the warranty.
EQUIVALENT SCHEMATIC
PATENTED
TYPICAL APPLICATION
Dynamic focusing is the active correction of focusing voltage
as a beam traverses the face of a CRT. This is necessary in
high resolution flat face monitors since the distance between
cathode and screen varies as the beam moves from the center
of the screen to the edges. PA85 lends itself well to this function
since it can be connected as a summing amplifier with inputs
from the nominal focus potential and the dynamic correction.
The nominal might be derived from a potentiometer, or per-
haps automatic focusing circuitry might be used to generate
this potential. The dynamic correction is generated from the
sweep voltages by calculating the distance of the beam from
the center of the display.
EXTERNAL CONNECTIONS
PHASE COMPENSATION
Gain CC RC
1 68pF 100Ω
20 10pF 330Ω
100 3.3pF 0Ω
CC RATED FOR FULL
SUPPLY VOLTAGE
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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ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, +VS to –VS 450V
OUTPUT CURRENT, continuous within SOA 200mA
POWER DISSIPATION, continuous @ TC = 25°C2 30W
INPUT VOLTAGE, differential ±25V
INPUT VOLTAGE, common mode ±VS
TEMPERATURE, pin solder - 10s max 300°C
TEMPERATURE, junction2 150°C
TEMPERATURE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C
PA85 • PA85A
SPECIFICATIONS
PA85 PA85A
PARAMETER TEST CONDITIONS 1 MIN TYP MAX MIN TYP MAX UNITS
INPUT
OFFSET VOLTAGE, initial .5 2 .25 .5 mV
OFFSET VOLTAGE, vs. temperature Full temperature range 10 30 5 10 µV/°C
OFFSET VOLTAGE, vs. supply 3 10 * * µV/V
OFFSET VOLTAGE, vs. time 75 * µV/√kh
BIAS CURRENT, initial3 5 50 3 10 pA
BIAS CURRENT, vs. supply .01 * pA/V
OFFSET CURRENT, initial3 10 100 3 30 pA
INPUT IMPEDANCE, DC 1011 * Ω
INPUT CAPACITANCE 4 * pF
COMMON MODE VOLTAGE RANGE4 ±VS–15 * V
COMMON MODE REJECTION, DC VCM = ±90V 90 110 * * dB
NOISE 100kHz BW, RS = 1KΩ, CC = 10pf 1 * µVrms
GAIN
OPEN LOOP, @ 15Hz RL = 2KΩ, CC = OPEN 96 111 * * dB
GAIN BANDWIDTH PRODUCT at 1MHz RL = 2KΩ, CC = 3.3pf 100 * MHz
POWER BANDWIDTH CC = 10pf 300 * kHz
CC = 3.3pf 500 * kHz
PHASE MARGIN Full temperature range 60 * °
OUTPUT
VOLTAGE SWING4 IO = ±200mA ±Vs–10 ±Vs–6.5 * * V
VOLTAGE SWING4 IO = ±75mA ±V–8.5 ±Vs–6.0 * * V
VOLTAGE SWING4 IO = ±20mA ±V–8.0 ±Vs–5.5 * * V
CURRENT, continuous TC = 85°C ±200 * mA
SLEW RATE, AV = 20 CC = 10pf 400 * V/µs
SLEW RATE, AV = 100 CC = OPEN 1000 700 * V/µs
CAPACITIVE LOAD, AV = +1 Full temperature range 470 * * pf
SETTLING TIME to .1% CC = 10pf, 2V step 1 * µs
RESISTANCE, no load RCL = 0 50 * Ω
POWER SUPPLY
VOLTAGE6 Full temperature range ±15 ±150 ±225 * * * V
CURRENT, quiescent 21 25 * * mA
THERMAL
RESISTANCE, AC, junction to case5 Full temperature range, F > 60Hz 2.5 * °C/W
RESISTANCE, DC, junction to case Full temperature range, F < 60Hz 4.2 * °C/W
RESISTANCE, junction to air Full temperature range 30 * °C/W
TEMPERATURE RANGE, case Meets full range specifications –25 +85 * * °C
NOTES: * The specification of PA85A is identical to the specification for PA85 in applicable column to the left.
1. Unless otherwise noted: TC = 25°C, compensation = CC = 68pF, RC = 100Ω. DC input specifications are ± value given. Power
supply voltage is typical rating.
2. Long term operation at the maximum junction temperature will result in reduced product life. Derate internal power dissipation to
achieve high MTTF. Ratings apply only to output transistors. An additional 10W may be dissipated due to quiescent power.
3. Doubles for every 10°C of temperature increase.
4. +VS and –VS denote the positive and negative power supply rail respectively.
5. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.
6. Derate max supply rating .625 V/°C below 25°C case. No derating needed above 25°C case.
The PA85 is constructed from MOSFET transistors. ESD handling procedures must be observed.
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
APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
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TYPICAL PERFORMANCE
GRAPHS PA85 • PA85A
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
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OPERATING
CONSIDERATIONS
PA85 • PA85A
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.
CURRENT LIMIT
For proper operation, the current limit resistor (RCL) must be
connected as shown in the external connection diagram. The
minimum value is 1.4 ohm, however for optimum reliability the
resistor value should be set as high as possible. The value
is calculated as follows; with the maximum practical value of
30 ohms.
.7
RCL =
ILIM - .016
SAFE OPERATING AREA (SOA)
The MOSFET output stage of this power operational ampli-
fier has two distinct limitations:
1. The current handling capability of the MOSFET geometry
and the wire bonds.
2. The junction temperature of the output MOSFETs.
NOTE: The output stage is protected against transient flyback.
However, for protection against sustained, high energy flyback,
external fast-recovery diodes should be used.
SAFE OPERATING CURVES
The safe operating area curves define the maximum ad-
ditional internal power dissipation the amplifier can tolerate
when it produces the necessary output to drive an external
load. This is not the same as the absolute maximum internal
power dissipation listed elsewhere in the specification since
the quiescent power dissipation is significant compared to
the total.
INPUT PROTECTION
Although the PA85 can withstand differential voltages up to
±25V, additional external protection is recommended. Since
the PA85 is a high speed amplifier, low leakage, low capaci-
tance JFETs connected as diodes are recommended (e.g.
2N4416, Q1-Q4 in Figure 2). The differential input voltage will
be clamped to ±1.4V. This is sufficient overdrive to produce
maximum power bandwidth.
POWER SUPPLY PROTECTION
Unidirectional zener diode transient suppressors are recom-
mended as protection on the supply pins. The zeners clamp
transients to voltages within the power supply rating and also
clamp power supply reversals to ground. Whether the zeners
are used or not, the system power supply should be evaluated
for transient performance including power-on overshoot and
power-off polarity reversals as well as line regulation.
Conditions which can cause open circuits or polarity reversals
on either power supply rail should be avoided or protected
against. Reversals or opens on the negative supply rail is
known to induce input stage failure. Unidirectional transzorbs
prevent this, and it is desirable that they be both electrically
and physically as close to the amplifier as possible.
STABILITY
The PA85 is externally compensated and performance can
be tailored to the application. Use the graphs of small signal
response and power response as a guide. The compensation
capacitor CC must be rated at 500V working voltage. An NPO
capacitor is recommended. The compensation network CCRC
must be mounted closely to the amplifier pins 7 and 8 to avoid
spurious oscillation.
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.
PA85U REV M OCTOBER 2003 © 2003 Apex Microtechnology Corp.
