Apex PA88, PA88A Datasheet

F

R

PA88

IN

R

PIEZO DRIVE

S

–V

S

+V

OUT

V

C

C

COMPUTER

FOCUS

COMMAND

VOLTAGE

MICROTECHNOLOGY

HTTP://WWW.APEXMICROTECH.COM (800) 546-APEX [phone]

FEATURES

• HIGH VOLTAGE — 450V (±225V)

• LOW QUIESCENT CURRENT — 2mA

• HIGH OUTPUT CURRENT — 100mA

• PROGRAMMABLE CURRENT LIMIT

• LOW BIAS CURRENT — FET Input

HIGH VOLTAGE POWER OPERATIONAL AMPLIFIERS

PA88 • PA88A

APPLICATIONS

PATENTED

• PIEZOELECTRIC POSITIONING

• HIGH VOLTAGE INSTRUMENTATION

• ELECTROSTATIC TRANSDUCERS

• PROGRAMMABLE POWER SUPPLIES UP TO 440V

TYPICAL APPLICATION

DESCRIPTION

The PA88 is a high voltage, low quiescent current MOSFET
operational amplifier designed for output currents up to 100mA.
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 PA88 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 beryllia (BeO) substrates, thick
film resistors, ceramic capacitors and semiconductor 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”.

EQUIVALENT SCHEMATIC

3

+V

Q18

CL

2

1

OUT

–V

6

S

S

D1

Q10B

Q4

+ IN

45

D19

COMP

Q16

D2

87

Q11

Q8

Q9

Q12

Q17

Q1 Q2

– IN

Q6 Q7

Q10A

Q13

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LOW POWER, PIEZOELECTRIC POSITIONING

Piezo positioning may be applied to the focusing of seg­mented mirror systems. The composite mirror may be com­posed of hundreds of elements, each requiring focusing under
computer control. In such complex systems the PA88’s advan­tage of low quiescent power consumption reduces the costs of
power supplies and cooling, while providing the interface
between the computer and the high voltage drive to the piezo
positioners.

EXTERNAL CONNECTIONS

R

+IN

–IN

CL

+Vs

3

4

TOP VIEW

5

6

–Vs

COMP

CL

2

1

8

7

R

C

PHASE COMPENSATION
GAIN

OUT

COMP

1
10
20

100

C

C

CC RATED FOR FULL
SUPPLY VOLTAGE

C

C

68pf
33pf
15pf

3.3pf

R

=

CL

100
100
100

.7

I

LIM

R

C

Ω
Ω
Ω

—

PA88 • PA88A

ABSOLUTE MAXIMUM RATINGS

SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

SUPPLY VOLTAGE, +VS to –V
OUTPUT CURRENT, source, sink See SOA

S

450V

POWER DISSIPATION, continuous @ TC = 25°C 15W
INPUT VOLTAGE, differential ±25V
INPUT VOLTAGE, common mode ±V
TEMPERATURE, pin solder - 10s max 300°C
TEMPERATURE, junction

2

S

150°C
TEMPERATURE, storage –65 to +150°C
OPERATING TEMPERATURE RANGE, case –55 to +125°C

SPECIFICATIONS

PARAMETER TEST CONDITIONS

PA88

1

MIN TYP MAX MIN TYP MAX UNITS

PA88A

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 1 5 * * µV/V
OFFSET VOLTAGE, vs. time 75 * µV/√kh
BIAS CURRENT, initial
BIAS CURRENT, vs. supply .01 * pA/V
OFFSET CURRENT, initial
INPUT IMPEDANCE, DC 10
INPUT CAPACITANCE 4 * pF
COMMON MODE VOLTAGE RANGE

3

3

4

±VS–12 * V

550 310pA

2.5 100 3 20 pA

11

* Ω

COMMON MODE REJECTION, DC VCM = ±90V 90 110 * * dB
NOISE 100kHz BW, RS = 1KΩ, CC = 15pf 2 * µVrms

GAIN

OPEN LOOP, @ 15Hz RL = 2KΩ, CC = OPEN 96 111 * * dB
GAIN BANDWIDTH PRODUCT at 1MHz RL = 2KΩ, CC = 15pf, RC = 100Ω 2.1 * MHz
POWER BANDWIDTH RL = 2KΩ, CC = 15pf, RC = 100Ω 6 * kHz
PHASE MARGIN Full temperature range 60 * °

OUTPUT

VOLTAGE SWING
VOLTAGE SWING
VOLTAGE SWING

4
4
4

IO = ±100mA ±VS–12 ±VS–9.8 * * V
Full temp. range, IO = ±75mA ±VS–8.5 ±VS–7.5 * * V

Full temp. range, IO = ±20mA ±VS–8.0 ±VS–5.2 * * V
CURRENT, continuous TC = 85°C ±100 * mA
SLEW RATE, AV = 20 CC = 15pf, RC = 100Ω 8*V/µs
SLEW RATE, AV = 100 CC = OPEN 30 * V/µs
CAPACITIVE LOAD, AV = +1 Full temperature range 470 * pf
SETTLING TIME to .1% CC = 15pf, RC = 100Ω, 2V step 10 * µs
RESISTANCE, no load RCL = 0 100 * Ω

POWER SUPPLY

VOLTAGE

6

See note 6 ±15 ±200 ±225 * * * V
CURRENT, quiescent, 1.7 2 * * mA

THERMAL

RESISTANCE, AC, junction to case

5

Full temperature range, F > 60Hz 5.0 * °C/W
RESISTANCE, DC, junction to case Full temperature range, F < 60Hz 8.3 * °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 PA88A is identical to the specification for PA88 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.

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.

CAUTION

The PA88 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.

APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: [phone]

TYPICAL PERFORMANCE
GRAPHS

PA88 • PA88A

15

POWER DERATING

12.5
T = T

10

C

7.5
T = T

5

A

2.5
0

0 25 50 75 100 125 150

INTERNAL POWER DISSIPATION, P(W)

120

TEMPERATURE, T (°C)

SMALL SIGNAL RESPONSE

100

C = 3.3pF

80
60

C = 33pF

C

40

20

0

OPEN LOOP GAIN, A (dB)

–20

1 10M

10 40

C

C = 15pF

C

C = 68pF

C

100 1K 10K .1M 1M

FREQUENCY, F (Hz)

50

SLEW RATE

30
20

µ

10

5
3

SLEW RATE, (V/ S)

2

PHASE RESPONSE

0
–30
–60

φ

–90

C = 68pF

–120

PHASE, (°)

–150
–180

–210

1 100 1K 1M

OUTPUT VOLTAGE SWING

12

SO

10

8

6

4

2

0

VOLTAGE DROP FROM SUPPLY, V – V (V)

HARMONIC DISTORTION

10

RL = 2K
P

1

A

V

.1

.01

DISTORTION, (%)

.001

C = 3.3pF

C

C = 33pF

C

C

C = 3.3pF

C = 33pF

C

C

C = 68pF

C

10 10K .1M

FREQUENCY, F (Hz)

C

T = 125°C

20

OUTPUT CURRENT, I (mA)

C

T = 85°C

C

T = 25°C

T = –55°C

C

60

80

O

Ω

= 2.5W

O

= 30

10M

100

QUIESCENT CURRENT

2.5

2.25

Q

2.0

1.75

1.5

T = 125°C

C

T = 25°C

C

T = -55°C

C

1.25

QUIESCENT CURRENT, I (mA)

1.0
0 100 300

200

TOTAL SUPPLY VOLTAGE, V (V)

POWER RESPONSE

500

PP

O

250

C = 68pf

125
100

75
50

OUTPUT VOLTAGE, V (V )

25

3K

1K 2K 100K

FREQUENCY, F (Hz)

20

√

15

N

10

7
5

3

C = 15pf

C = 33pf

C

C

C

5K

10K 20K 50K

INPUT NOISE

450

S

C = 3.3pf

C

1

050

COMPENSATION CAPACITOR, C

20 60

40

7010 30 3

(pF)

C

COMMON MODE REJECTION

120

100

80

60

40

20

1K 10K

110 1M

COMMON MODE REJECTION, CMR (dB)

100 .1M

FREQUENCY, F (Hz)

.0001

30K30 300 3K

2

INPUT NOISE VOLTAGE, V (nV/ Hz)

10 100 10K 1M

FREQUENCY, F (Hz)

POWER SUPPLY REJECTION

140

120

100

80

60

40
20

11M

POWER SUPPLY REJECTION, PSR (dB)

10 100 1K 10K .1M

FREQUENCY, F (Hz)

200

120
100

LIM

70
50

30
20

CURRENT LIMIT, I (mA)

10

550

3 10 20 100

CURRENT LIMIT RESISTOR, R

1K

FREQUENCY, F (Hz)

CURRENT LIMIT

150

( )

Ω

CL

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PA88 • PA88A

OPERATING

CONSIDERATIONS

GENERAL

Please read the “General Operating Considerations” sec­tion, which covers stability, supplies, heatsinking, mounting,
current limit, SOA interpretation, and specification interpreta­tion. 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 3.5 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 150
ohms.

R

CL

.7

=

I

LIM

SAFE OPERATING AREA (SOA)

The MOSFET output stage of this power operational ampli­fier 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.

250

200mS

DC, T

C

= 85°C

100mS

= 25°C

150

, (mA)

S

100

OR –V

S

50

25

DC, T

DC, T

C

= 125°C

C

applications 1N4148 or 1N914 signal diodes are sufficient (D1,
D2 in Figure 2a). In more demanding applications where low
leakage or low capacitance are of concern 2N4416 or 2N5457­2N5459 JFETs connected as diodes will be required (Q1, Q2
in Figure 2b). In either case the input differential voltage will be
clamped to ±.7V. This is sufficient overdrive to produce maxi­mum power bandwidth.

POWER SUPPLY PROTECTION

Unidirectional zener diode transient suppressors are recom­mended 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 reversal 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 PA88 has sufficient phase margin to be stable with most
capacitive loads at a gain of 4 or more, using the recommended
phase compensation.

The PA88 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 C
rated at 500V working
voltage. An NPO capaci­tor is recommended. The
compensation network
C

must be mounted

CRC

closely to the amplifier
pins 7 and 8 to avoid
spurious oscillation.

must be

C

a.

–IN

+IN

+V

S

Z1

3

5

D2D1

PA88

4

6

15

10

OUTPUT CURRENT FROM +V

PULSE CURVES @ 10% DUTY CYCLE MAX

5

25 50 75 100 250 500

SUPPLY TO OUTPUT DIFFERENTIAL, VS –VO (V)

125

However, for protection against sustained, high energy flyback,
external fast-recovery diodes should be used.

b.

–IN

Q1 Q2

+IN

5

4

–V

S

+V

S

PA88

Z2

Z1

3

6

INPUT PROTECTION

–V

Z2

S

Although the PA88 can withstand differential input voltages
up to ±25V, additional external protection is recommended,
and required at total supply voltages above 300 volts. In most

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.

PA88U REV. I MARCH 1999 © 1999 Apex Microtechnology Corp.

FIGURE 2. OVERVOLTAGE PROTECTION