AN10436 PHILIPS [NXP Semiconductors], AN10436 Datasheet - Page 36

• Manufacturer Part Number: AN10436
• Description: TDA8932B/33(B) Class-D audio amplifier
• Manufacturer: PHILIPS [NXP Semiconductors]

NXP Semiconductors
AN10436_1
Application note
3.9.2 Thermal considerations
In general:
The thermal resistance is determined by the selected SMD package, the PCB layout
implementation and the airflow inside the final enclosure of the amplifier.
The TDA8932B/33(B) is available in two different thermally enhanced SMD packages:
Thermal resistance SO32 package
The SO32 package has special thermal corner leads, pins 1, 16, 17 and 32, increasing
the power capability (reducing the overall R
at V
designs with limited space for a thermal plane. Due to the package size the SO32 is able
to radiate a significant part of the heat directly into the air (thermal resistance is less
depending on the heat transfer via the PCB).
The thermal resistance of a S032 package will range from about 35 K/W to 50 K/W when
mounted on a single or two layer PCB (free air natural convection). Mounting a heat sink
can further decrease the thermal resistance with another 15 % to 25 %.
The thermal resistance measured at the compact reference PCB (55 mm × 45 mm) with
S032 package can be found in
Thermal resistance HTSSOP32 package
The HTSSOP32 package has an exposed die-pad that only reduces the overall R
significantly when soldered to a thermal copper plane at V
strongly depending on the size and the number of copper planes). This makes the
HTSSOP package very suitable for multilayer PCB designs with sufficient space for two or
three thermal copper planes. When applying three thermal copper planes it is even
possible to reach a continuous time output power of 2 × 25 W without a heat sink.
The thermal resistance of a HTSSOP32 package will range from about 25 K/W to 55 K/W
when mounted on a multilayer PCB without heat sink (free air natural convection).
Increasing the area of the thermal copper planes, the number of planes, or the copper
thickness will further reduce the thermal resistance R
•
•
•
•
Minimizing the current loops that carry fast alternating currents will reduce magnetic
radiation.
Minimizing the length / size of the PWM output track (fast alternating voltages) as
much as possible, will prevent capacitive coupling to the environment. Otherwise this
could lead to disturbances of high impedance inputs.
TDA8932BT/33T in SO32 (SOT287-1) package for reflow and wave solder process.
TDA8932BTW/33BTW in an HTSSOP32 (SOT549-1) package for reflow solder
process only.
SSA
level. The SO package is very suitable for single layer PCB designs or PCB
Rev. 01 — 12 December 2007
Section
5.3.
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TDA8932B/33(B) Class-D audio amplifier
) when soldered to a thermal copper plane
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SSA
of both packages.
level (thermal resistance is
AN10436
© NXP B.V. 2007. All rights reserved.
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