SA58632 Datasheet, PDF (11/26 Pages) NXP Semiconductors – 2 x 2.2 W BTL audio amplifier

Philips Semiconductors
SA58632
2 × 2.2 W BTL audio amplifier
14.3 Thermal behavior
The measured thermal performance of the HVQFN20 package is highly dependent on the
configuration and size of the heat spreader on the application demo board. Data may not
be comparable between different semiconductors manufacturers because the application
demo boards and test methods are not standardized. Also, the thermal performance of
packages for a specific application may be different than presented here, because of the
configuration of the copper heat spreader of the application boards may be significantly
different.
Philips Semiconductors uses FR-4 type application boards with 1 ounce copper traces
with solder coating.
The demo board (see Figure 23) has a 1 ounce copper heat spreader that runs under the
IC and provides a mounting pad to solder to the die attach paddle of the HVQFN20
package. The heat spreader is symmetrical and provides a heat spreader on both top and
bottom of the PCB. The heat spreader on top and bottom side of the demo board is
connected through 2 mm diameter plated through holes. Directly under the DAP (Die
Attach Paddle), the top and bottom side of the PCB are connected by four vias. The total
top and bottom heat spreader area is 64.5 mm² (10 in²).
The junction to ambient thermal resistance, R_th(j-a) = 22 K/W for the HVQFN20 package
when the exposed die attach paddle is soldered to 5 square inch area of 1 ounce copper
heat spreader on the demo PCB. The maximum sine wave power dissipation for
T_amb = 25 °C is:
1_----5_---0_-2---–_2-----2_---5_{- = 5.7 W}
Thus, for T_amb = 60 °C the maximum total power dissipation is:
1_----5_---0_-2---–_2-----6_---0_{- = 4.1 W}
The power dissipation versus ambient temperature curve (Figure 10) shows the power
derating profiles with ambient temperature for three sizes of heat spreaders. For a more
modest heat spreader using 5 square inch area on the top or bottom side of the PCB, the
R_th(j-a) is 31 K/W. When the package is not soldered to a heat spreader, the R_th(j-a)
increases to 60 K/W.
SA58632_1
Product data sheet
Rev. 01 — 27 June 2006
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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