APEX MICROTECHNOLOGY CORPORATION · TELEPHONE (520) 690-8600 · FAX (520) 888-3329 · ORDERS (520) 690-8601 · EMAIL prodlit@apexmicrotech.com

FEATURES

· LOW THERMAL RESISTANCE -- 1.4°C/W

· CURRENT FOLDOVER PROTECTION -- NEW

· HIGH TEMPERATURE VERSION -- PA12H

· EXCELLENT LINEARITY -- Class A/B Output

· WIDE SUPPLY RANGE -- ±10V to ±50V

· HIGH OUTPUT CURRENT -- Up to ±15A Peak

APPLICATIONS

· MOTOR, VALVE AND ACTUATOR CONTROL

· MAGNETIC DEFLECTION CIRCUITS UP TO 10A

· POWER TRANSDUCERS UP TO 100kHz

· TEMPERATURE CONTROL UP TO 360W

· PROGRAMMABLE POWER SUPPLIES UP TO 90V

· AUDIO AMPLIFIERS UP TO 120W RMS

DESCRIPTION

The PA12 is a state of the art high voltage, very high

output current operational amplifier designed to drive resis-

tive, inductive and capacitive loads. For optimum linearity,

especially at low levels, the output stage is biased for class

A/B operation using a thermistor compensated base-emitter

voltage multiplier circuit. The safe operating area (SOA) can

be observed for all operating conditions by selection of user

programmable current limiting resistors. For continuous opera-

tion under load, a heatsink of proper rating is recommended.

The PA12 is not recommended for gains below 3 (inverting)

or +4 (non-inverting).

This hybrid integrated circuit utilizes thick film (cermet)

resistors, ceramic capacitors and semiconductor chips to
maximize reliability, minimize size and give top performance.
Ultrasonically bonded aluminum wires provide reliable inter-
connections at all operating temperatures. The 8-pin TO-3
package is hermetically sealed and electrically isolated. The
use of compressible isolation washers voids the warranty.

EQUIVALENT SCHEMATIC

POWER RATING

Not all vendors use the same method to rate the power han-

dling capability of a Power Op Amp. APEX rates the internal

dissipation, which is consistent with rating methods used by

transistor manufacturers and gives conservative results. Rating

delivered power is highly application dependent and therefore

can be misleading. For example, the 125W internal dissipation

rating of the PA12 could be expressed as an output rating of

250W for audio (sine wave) or as 440W if using a single ended

DC load. Please note that all vendors rate maximum power
using an infinite heatsink.

THERMAL STABILITY

APEX has eliminated the tendency of class A/B output

stages toward thermal runaway and thus has vastly increased
amplifier reliability. This feature, not found in most other Power
Op Amps, was pioneered by APEX in 1981 using thermistors
which assure a negative temperature coefficient in the quies-
cent current. The reliability benefits of this added circuitry far
outweigh the slight increase in component count.

EXTERNAL CONNECTIONS

8-PIN TO-3

PACKAGE STYLE CE

APEX MICROTECHNOLOGY CORPORATION · 5980 NORTH SHANNON ROAD · TUCSON, ARIZONA 85741 · USA · APPLICATIONS HOTLINE: 1 (800) 546-2739

ABSOLUTE MAXIMUM RATINGS

SPECIFICATIONS

SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

PA12

PA12A

PARAMETER

TEST CONDITIONS

2, 5

MIN

TYP

MAX

MIN

TYP

MAX

UNITS

INPUT

OFFSET VOLTAGE, initial

= 25°C

±2

±6

±1

±4

OFFSET VOLTAGE, vs. temperature

Full temperature range

±10

±65

±40

µV/°C

OFFSET VOLTAGE, vs. supply

= 25°C

±30

±200

µV/V

OFFSET VOLTAGE, vs. power

= 25°C

±20

µV/W

BIAS CURRENT, initial

= 25°C

±12

±30

BIAS CURRENT, vs. temperature

Full temperature range

±50

±500

pA/°C

BIAS CURRENT, vs. supply

= 25°C

±10

pA/V

OFFSET CURRENT, initial

= 25°C

±12

±30

±5

±20

OFFSET CURRENT, vs. temperature

Full temperature range

±50

pA/°C

INPUT IMPEDANCE, DC

= 25°C

200

INPUT CAPACITANCE

= 25°C

COMMON MODE VOLTAGE RANGE

Full temperature range

±V

5 ±V

COMMON MODE REJECTION, DC

Full temp. range, V

= ±V

100

GAIN

OPEN LOOP GAIN at 10Hz

= 25°C, 1K load

110

OPEN LOOP GAIN at 10Hz

Full temp. range, 8 load

108

GAIN BANDWIDTH PRODUCT @ 1MHz

= 25°C, 8 load

MHz

POWER BANDWIDTH

= 25°C, 8 load

kHz

PHASE MARGIN, A

= +4

Full temp. range, 8 load

OUTPUT

VOLTAGE SWING

= 25°C, PA12 = 10A, PA12A = 15A

±V

VOLTAGE SWING

= 25°C, I

= 5A

±V

VOLTAGE SWING

Full temp. range, I

= 80mA

±V

CURRENT, peak

= 25°C

SETTLING TIME to .1%

= 25°C, 2V step

µs

SLEW RATE

= 25°C

2.5

V/µs

CAPACITIVE LOAD

Full temperature range, A

= 4

1.5

CAPACITIVE LOAD

Full temperature range, A

> 10

SOA

POWER SUPPLY

VOLTAGE

Full temperature range

±10

±40

±45

±50

CURRENT, quiescent

= 25°C

THERMAL

RESISTANCE, AC, junction to case

= 55 to +125°C, F > 60Hz

°C/W

RESISTANCE, DC, junction to case

= 55 to +125°C

1.25

1.4

°C/W

RESISTANCE, junction to air

= 55 to +125°C

°C/W

TEMPERATURE RANGE, case

Meets full range specification

+85

+125

°C

PA12 · PA12A

NOTES: * The specification of PA12A is identical to the specification for PA12 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 ±40, unless otherwise noted as a test condition.

3. +V

and V

denote the positive and negative supply rail respectively. Total V

is measured from +V

to V

4. Rating applies if the output current alternates between both output transistors at a rate faster than 60Hz.

5. Full temperature range specifications are guaranteed but not 100% tested.

PA12/PA12A

SUPPLY VOLTAGE, +Vs to Vs

100V

OUTPUT CURRENT, within SOA

15A

POWER DISSIPATION, internal

125W

INPUT VOLTAGE, differential

±V

INPUT VOLTAGE, common mode

±V

TEMPERATURE, pin solder -10s

300°C

TEMPERATURE, junction

200°C

TEMPERATURE RANGE, storage

65 to +150°C

OPERATING TEMPERATURE RANGE, case

55 to +125°C

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 · 5980 NORTH SHANNON ROAD · TUCSON, ARIZONA 85741 · USA · APPLICATIONS HOTLINE: 1 (800) 546-2739

load and short circuits to the supply rail or common if the

current limits are set as follows at T

= 25°C:

SHORT TO ±V

SHORT TO

±V

C, L, OR EMF LOAD

COMMON

50V

.30A

2.4A

40V

.58A

2.9A

35V

.87A

3.7A

30V

1.5A

4.1A

25V

2.4A

4.9A

20V

2.9A

6.3A

15V

4.2A

8.0A

These simplified limits may be exceeded with further analysis

using the operating conditions for a specific application.

CURRENT LIMITING

Refer to Application Note 9, "Current Limiting", for details of

both fixed and foldover current limit operation. Visit the Apex

web site at www.apexmicrotech.com for a copy of the Power

Design spreadsheet (Excel) which plots current limits vs. steady

state SOA. Beware that current limit should be thought of as a

+/20% function initially and varies about 2:1 over the range

of 55°C to 125°C.

For fixed current limit, leave pin 7 open and use equations

1 and 2.

= 0.65/L

(1)

= 0.65/R

(2)

Where:

is the current limit in amperes.

is the current limit resistor in ohms.

For certain applications, foldover current limit adds a slope

to the current limit which allows more power to be delivered

to the load without violating the SOA. For maximum foldover

slope, ground pin 7 and use equations 3 and 4.

0.65 + (Vo * 0.014)

(3)

0.65 + (Vo * 0.014)

(4)

Where:

Vo is the output voltage in volts.
Most designers start with either equation 1 to set R

for the

desired current at 0v out, or with equation 4 to set R

at the

maximum output voltage. Equation 3 should then be used to

plot the resulting foldover limits on the SOA graph. If equa-

tion 3 results in a negative current limit, foldover slope must

be reduced. This can happen when the output voltage is the

opposite polarity of the supply conducting the current.

In applications where a reduced foldover slope is desired,

this can be achieved by adding a resistor (R

) between pin

7 and ground. Use equations 4 and 5 with this new resistor
in the circuit.

Vo * 0.14

0.65 +

10.14 + R

(5)

Vo * 0.14

0.65 +

10.14 + R

(6)

Where:

is in K ohms.

OPERATING

CONSIDERATIONS

PA12 · PA12A

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,

internal power dissipation, current limit; heat sink selection;

Apex's complete Application Notes library; Technical Seminar

Workbook; and Evaluation Kits.

SAFE OPERATING AREA (SOA)

The output stage of most power amplifiers has three distinct

limitations:

1. The current handling capability of the transistor geometry

and the wire bonds.

2. The second breakdown effect which occurs whenever the

simultaneous collector current and collector-emitter voltage

exceeds specified limits.

3. The junction temperature of the output transistors.

The SOA curves combine the effect of all limits for this Power

Op Amp. 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. Capacitive and dynamic* inductive loads up to the following

maximum are safe with the current limits set as specified.

CAPACITIVE LOAD

INDUCTIVE LOAD

±V

LIM

= 5A

LIM

= 10A

LIM

= 5A

LIM

= 10A

50V

200µF

125µF

5mH

2.0mH

40V

500µF

350µF

15mH

3.0mH

35V

2.0mF

850µF

50mH

5.0mH

30V

7.0mF

2.5mF

150mH

10mH

25V

25mF

10mF

500mH

20mH

20V

60mF

20mF

1,000mH

30mH

15V

150mF

60mF

2,500mH

50mH

*If the inductive load is driven near steady state conditions,

allowing the output voltage to drop more than 8V below the

supply rail with I

LIM

= 15A or 25V below the supply rail with I

LIM

= 5A while the amplifier is current limiting, the inductor must

be capacitively coupled or the current limit must be lowered

to meet SOA criteria.
2. The amplifier can handle any EMF generating or reactive

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.

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