GENERAL
CONSIDERATIONS
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.
SAFE OPERATING AREA (SOA)
TheSOAcurvescombinetheeffectofalllimitsforthispower
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.
THERMAL CONSIDERATIONS
�
ꢀ
ꢁ
ThePA62DKhasalargeexposedintegratedcopperheatslug
towhichthemonolithicisdirectlyattached. Thesolderconnec-
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.Otherhighlythermalconductivesubstrateboardmaterials
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).
ꢊꢋꢌꢍꢎꢏꢐꢏꢈꢑꢒꢓꢌꢔꢌꢕꢖꢋꢏꢔꢖꢀꢑꢏꢂꢃꢄꢅ
ꢈꢋꢏꢐꢏꢒꢗꢈꢋꢕꢏꢑꢀꢘꢀꢖꢏꢉꢖꢌꢙꢕꢖꢚ
ꢂꢃꢄꢅ
ꢆꢇꢈꢉ
FIGURE 4. 3 Phase Inverter
GENERAL
PleasereadApplicationNote1"GeneralOperatingConsider-
ations"whichcoversstability, supplies, heatsinking, mounting,
SOAinterpretation, andspecificationinterpretation. Visitwww.
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(bothdevicesareNPN)outputstageswith
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.
�ꢀꢁꢂꢃꢄꢅꢂꢃꢆꢇꢈꢉꢊ
ꢖꢔ
ꢙꢔ
ꢚꢔ
ꢕꢔ
ꢘꢔ
ꢔ
�ꢀꢁ
ꢘꢟ
ꢇꢔꢐꢄꢅꢔꢄꢛꢄꢙꢜꢝꢔ
ꢗꢄꢍꢕꢁꢂꢈꢉꢈꢊꢋ�ꢄꢂꢆꢍꢇꢊꢇ
ꢚꢄꢍꢕꢁꢂꢈꢉꢈꢊꢋ�ꢄꢂꢆꢍꢇꢊꢇ
ꢙꢄꢍꢕꢁꢂꢈꢉꢈꢊꢋ�ꢄꢂꢆꢍꢇꢊꢇ
ꢘꢕꢖ
ꢔ
ꢕꢖ
�ꢀꢁꢂꢃꢄꢅꢁꢆꢃꢇꢈꢉꢇꢊꢋꢃꢀꢊꢇꢌꢆꢃ�ꢆꢍꢎꢂꢏ
ꢖꢔ
ꢗꢖ
ꢘꢔꢔ
ꢘꢄꢍꢕꢁꢂꢈꢉꢈꢊꢋ�ꢄꢂꢆꢍꢇꢊꢇ
ꢘ
MOUNTING PRECAUTIONS
1. Always use a heat sink. Even unloaded the PA62DK can
dissipate up to .8 watts.
ꢇꢔꢐꢄꢅꢔꢄꢛꢄꢞꢜꢝꢔ
2. Avoid bending the leads. Such action can lead to internal
damage.
ꢟꢠꢘ
ꢘ
ꢘꢟ
ꢜꢟ
�ꢀꢁꢁꢂꢃꢄꢅꢆꢄꢆꢀꢅꢁꢀꢅꢄꢇꢈꢉꢉꢊꢋꢊꢌꢅꢈꢍꢂꢄꢎꢆꢂꢅꢍꢏꢊꢐꢄꢎ�ꢄꢑꢄꢎꢆꢄꢒꢎꢓ
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.
4APEX MICROTECHNOLOGY CORPORATION • 5980 NORTH SHANNON ROAD • TUCSON, ARIZONA 85741 • USA • APPLICATIONS HOTLINE: 1 (800) 546-2739
PA62U REV C OCTOBER 2005
© 2005 Apex Microtechnology Corp.
APEX [ CIRRUS LOGIC ]
