P r o d u c t I n n o v a t i o n F r o m

PA02 • PA02A

4

PA02U

general

Please read Application Note 1 "General Operating Considerations" which cov-

ers stability, supplies, heat sinking, mounting, current limit, SOA interpretation, and

specification interpretation. Visit www.Cirrus.com for design tools that help automate

tasks such as calculations for stability, internal power dissipation, current limit; heat

sink selection; Apex Precision Power’s complete Application Notes library; Technical

Seminar Workbook; and Evaluation Kits.

saFeoperatingarea

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 cal-

culated or measured and checked

against the SOA curves. This is

simple for resistive loads but more

complex for reactive and EMF

generating loads. The following

guidelines may save extensive

analytical efforts:

1. Under transient conditions,

capacitive and dynamic* loads

up to the following maximums

are safe:

CAPACITIVE LOAD

INDUCTIVE LOAD

±V

S

I

I

I

I

18V

2mF

0.7mF

.2H

10mH

15V

10mF

2.2mF

.7H

25mH

10V

25mF

10mF

5H

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

supply rail with I

be capacitively coupled or the current limit must be lowered to meet SOA criteria.

2. The amplifier can handle any EMF generating or reactive load and short circuits

to the supply rails or shorts to common if the current limits are set as follows at

T

SHORT TO ±V

S

SHORT TO

±V

S

C, L OR EMF LOAD

COMMON

18V

.5A

1.7A

15V

.7A

2.8A

10V

1.6A

4.2A

These simplified limits may be exceeded with further analysis using the operating

conditions for a specific application.

currentlimit

Proper operation requires the use of two current limit resistors, connected as shown

in the external connection diagram.The minimum value for R

optimum reliability it should be set as high as possible. Refer to the “General Operating

Considerations” section of the handbook for current limit adjust details.

deVicemounting

The case (mounting flange) is electrically isolated and should be mounted directly

to a heatsink with thermal compound. Screws with Belville spring washers are recom-

mended to maintain positive clamping pressure on heatsink mounting surfaces. Long

periods of thermal cycling can loosen mounting screws and increase thermal resistance.

Since the case is electrically isolated (floating) with respect to the internal circuits

it is recommended to connect it to common or other convenient AC ground potential.

2

3

5

7

10

15 20 25 30 40

0.2

0.3

0.5

0.7

1.0

1.5

2.0

3.0

4.0

5.0

THERMAL

T

C

= 125

°C

T

C

= 25°C

T

C

= 70

°C

T

C

= 100

°C

SOA

100

1K

3K

.1M

FREQUENCY, F (Hz)

.001

.1

1

HARMONIC DISTORTION

.003

.03

.3

300

10K 30K

.01

.3M

1

3

4

TIME, t (µS)

–15

5

15

PULSE RESPONSE

–10

0

10

2

5

–5

PULSE RESPONSE

–.2

–.1

0

.1

.2

.3

–.3

10K

FREQUENCY, F (Hz)

LOADING EFFECTS

–1.2

–.6

0

.1M

100

1K

–1.5

–.9

–.3

TIME, t (µS)

0

.5

1.0

1.5

0

GAIN = 1

LOAD = 10Ω

5W

= 50mW

= .5W

V

V

LOAD = 10Ω

I

I