APEX MICROTECHNOLOGY CORPORATION • TELEPHONE (520) 690-8600 • FAX (520) 888-3329 • ORDERS (520) 690-8601 • EMAIL prodlit@apexmicrotech.com
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 MOSFET
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 pro-
vides user flexibility.
This hybrid circuit utilizes thick film (cermet) resistors, ce-
ramic capacitors and silicon semiconductor chips to maximize
reliability, minimize size and give top performance. Ultrasoni-
cally bonded aluminum wires provide reliable interconnec-
tions at all operating temperatures. The 8-pin TO-3 package is
hermetically sealed and electrically isolated. The use of com-
pressible isolation washers voids the warranty.
EQUIVALENT SCHEMATIC
2
1
3
6
45
87
COMP C
OUT
+V
S
–V
S
L
Q1 Q2 Q4 Q8 Q9
Q6 Q7 Q12
Q10A Q10B Q11
Q17
Q13 Q16
Q18
D1
D23
D2
–IN +IN
PATENTED
TYPICAL APPLICATION
Dynamic focusing is the active correction of focusing volt-
age as a beam traverses the face of a CRT. This is necessary
in high resolution flat face monitors since the distance be-
tween 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 potentiom-
eter, or perhaps 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
2
z = x + y
2
IN1
R
F
R
CL
R
+225V
–225V
PA85
IN2
R
DC
FOCUS
X SWEEP
SAMPLE
Y SWEEP
SAMPLE
TO
FOCUS
GRID
1
2
3
4
5
67
8
TOP VIEW
CL
+Vs
+IN
–Vs
COMP
OUT
R
CL
–IN
C
C
COMP R
C
PHASE COMPENSATION
Gain CCRC
1 68pF 100Ω
20 10pF 330Ω
100 3.3pF 0Ω
CC RATED FOR FULL
SUPPLY VOLTAGE
HTTP://WWW.APEXMICROTECH.COM (800) 546-APEX (800) 546-2739
MICROTECHNOLOGY
HIGH VOLTAGE POWER OPERATIONAL AMPLIFIERS
PA85 • PA85A
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
ABSOLUTE MAXIMUM RATINGS
SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS SUPPLY VOLTAGE, +VS to –VS450V
OUTPUT CURRENT, continuous within SOA 200mA
POWER DISSIPATION, continuous @ TC = 25°C230W
INPUT VOLTAGE, differential ±25V
INPUT VOLTAGE, common mode ±VS
TEMPERATURE, pin solder - 10s max 300°C
TEMPERATURE, junction2150°C
TEMPERATURE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C
PA85 • PA85A
SPECIFICATIONS
PARAMETER TEST CONDITIONS1MIN 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, initial3550 310pA
BIAS CURRENT, vs. supply .01 * pA/V
OFFSET CURRENT, initial310 100 3 30 pA
INPUT IMPEDANCE, DC 1011 *Ω
INPUT CAPACITANCE 4 * pF
COMMON MODE VOLTAGE RANGE4±VS–12 * 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 SWING4IO = ±200mA ±Vs–10 ±Vs–6.5 * * V
VOLTAGE SWING4IO = ±75mA ±V–8.5 ±Vs–6.0 * * V
VOLTAGE SWING4IO = ±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
VOLTAGE6Full temperature range ±15 ±150 ±225 * * * V
CURRENT, quiescent 21 25 * * mA
THERMAL
RESISTANCE, AC, junction to case5Full 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
PA85A
PA85
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
TYPICAL PERFORMANCE
GRAPHS PA85 • PA85A
0 25 50 75 100 125 150
CASE TEMPERATURE, T (°C)
0
8
24
32
POWER DERATING
OUTPUT STAGE
INTERNAL POWER DISSIPATION, P(W)
.2M FREQUENCY F (Hz)
–225
–45
0
PHASE RESPONSE
PHASE, (°)
–270
10 100 10K 100K
FREQUENCY, F (Hz)
INPUT NOISE VOLTAGE, V (nV/ Hz)
10
10M
FREQUENCY, F (Hz)
–20
0
60
120
SMALL SIGNAL RESPONSE
OPEN LOOP GAIN, A (dB)
20
40
80
100
0250
OUTPUT CURRENT, I (mA)
4
5
8
10
OUTPUT VOLTAGE SWING
7
9
500K
5M
FREQUENCY, F (Hz)
25
125
500
OUTPUT VOLTAGE, V (V )
O
100
250
1K 10K 10M
FREQUENCY, F (Hz)
20
80
140
COMMON MODE REJECTION
COMMON MODE REJECTION, CMR (dB)
40
60
100
11M
FREQUENCY, F (Hz)
20
40
140
POWER SUPPLY REJECTION
POWER SUPPLY REJECTION, PSR (dB)
60
100
1 5 10 30
RESISTOR VALUE, R ( )
20
100
500
CURRENT LIMIT
CURRENT LIMIT, I (mA)
LIM
200
300
060
EXT. COMPENSATION CAPACITOR, C (pF)
100
SLEW RATE
SLEW RATE, (V/ S)
200
1000
9015 45 10 FREQUENCY, F (Hz)
.003
HARMONIC DISTORTION
DISTORTION, (%)
.03
.05
100K100 1K 10K
0 100 300 400
TOTAL SUPPLY VOLTAGE, V (V)
.90
1.10
QUIESCENT CURRENT
NORMALIZED QUIESCENT CURRENT, I (X)
Q
1.05
S
100K 1M
CL
220
50
INPUT NOISE VOLTAGE
1K
2
7
10
20
5
3
15
N
√
O
100
VOLTAGE DROP FROM SUPPLY, V – V (V)
SO
–135
16
40
POWER RESPONSE
PP
10 100 1K 10K .1M
80
200
.95
1.00
µ
C
Φ
Ω
.001
100 1K 10K .1M 1M
–180
–90
C
450
1.15
1.20
C = 10pF
C
200
6
T = 125°C
C
T = 125°C
C
T = 25°C
C
T = 25°C
C
T = –55°C
C
T = –55°C
C
75
50
1M
500
30 75
.005
.01
O
C
A
V
= 30
P = 15W
C = 10pf
R = 1KΩ
L
120 C = 10pF
C
120
C = 3.3pf
C
C = 10pf
C
C = 68pf
C
R = 2K Ω
L
2M50K 100K 200K
C = 68pF
C
C = 10pF
C
C = 3.3pF
C
20M
1M 10M 40M
C = 68pF
C
C = 3.3pF
C
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
OPERATING
CONSIDERATIONS
PA85 • PA85A
GENERAL
Please read the “General Operating Considerations” sec-
tion, which covers stability, supplies, heatsinking, mounting,
current limit, SOA interpretation, and specification interpreta-
tion. Additional information can be found in the application
notes. For information on the package outline, heatsinks, and
mounting hardware, consult the “Accessory and Package
Mechanical Data” section of the handbook.
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 addi-
tional 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
SUPPLY TO OUTPUT DIFFERENTIAL, VS –VO (V)
25 50 75 100 250 500
OUTPUT CURRENT FROM +VS OR –VS, (mA)
10
20
30
50
100
200
300
500
DC, T
C
= 125°C
DC, T
C
= 85°C
200mS
PULSE CURVES @ 10% DUTY CYCLE MAX
DC, T
C
= 25°C
100mS
125
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 rever-
sals 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.
+VS
–IN
+IN
Z1
Z2
3
6
5
4
PA85
Q1
Q2
–VS
Q3
Q4
FIGURE 2
OVERVOLTAGE
PROTECTION
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. L JANUARY 1998 © 1998 Apex Microtechnology Corp.
