PA62
TYPICAL APPLICATION (CONT.)
The PA62 can be used in a three amplifier configuration for
a three phase inverter or motor as shown in Figure 4.
GENERAL
CONSIDERATIONS
SAFE OPERATING AREA (SOA)
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. The following guidelines may save extensive analyti-
cal efforts.
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THERMAL CONSIDERATIONS
The PA62DK has a large exposed integrated copper heatslug
to which the monolithic is directly attached. The solder connec-
tion of the heatslug to a minimum of 1 square inch foil area of
the printed circuit board will result in thermal performance of
25°C/W junction to air rating of the PA62DK. Solder connec-
tion to an area of 1 to 2 square inches of foil is required for
minimal power applications
Where the PA62DK is used in higher power applications,
it is necessary to use surface mount techniques of heatsink-
ing. Surface mount techniques include the use of a surface
mount fan in combination with a surface mount heatsink on
the backside of the FR4/ PC board with through hole thermal
vias. Other highly thermal conductive substrate board materials
are available for maximum heat sinking.
The Power Derating graph shown below assumes that the
power dissipation is equal in each of the amplifiers. Power and
thermal ratings are based on two separate dual monolithic
power op amps on one integrated copper heat slug. Amps A
and B are combined on one monolithic die while amps C and
D are combined on the other. This multi chip configuration
provides superior thermal performance by isolating each of
the dual amplifiers. When loading either of the dual amplifiers
it is possible to achieve better thermal performance by loading
any combination of amplifiers (A or B) + (C or D).
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FIGURE 4.
3 Phase Inverter
GENERAL
Please read Application Note 1 "General Operating Consider-
ations" which covers stability, supplies, heatsinking, mounting,
SOA interpretation, and specification interpretation. Visit www.
apexmicrotech.com for design tools that help automate tasks
such as calculations for stability, internal power dissipation,
heatsink selection; Apex's complete Application Notes library;
Technical Seminar Workbook; and Evaluation Kits.
STABILITY CONSIDERATIONS
All monolithic power op amps use output stage topologies
that present special stability problems. This is primarily due to
non-complementary (both devices are NPN) output stages with
a mismatch in gain and phase response for different polarities
of output current. It is difficult for the op amp manufacturer to
optimize compensation for all operating conditions.
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MOUNTING PRECAUTIONS
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1. Always use a heat sink. Even unloaded the PA62DK can
dissipate up to .8 watts.
2. Avoid bending the leads. Such action can lead to internal
damage.
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This data sheet has been carefully checked and is believed to be reliable,
SHANNON ROAD •
is assumed
ARIZONA 85741 • USA • APPLICATIONS
are subject
1 (800) 546-2739
APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH
however, no responsibility
TUCSON,
for possible inaccuracies or omissions. All specifications
HOTLINE:
to change without notice.
4
PA62U REV C OCTOBER 2005 © 2005 Apex Microtechnology Corp.
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