Datasheet

THERMAL AND PACKAGE INFORMATION
PRINTED-CIRCUIT BOARD (PCB) LAYOUT
BASIC MEASUREMENT SYSTEM
TAS5602
www.ti.com ................................................................................................................................................... SLAS593B – JUNE 2008 – REVISED NOVEMBER 2008
The TAS5602DCA package is the DCA 56-pin TSSOP package. To estimate the junction temperature using
measurable parameters, a thermal metric θ
JT
is modeled, which relates the temperature at the top of the package
to the junction temperature, T
J
. For TAS5602DCA, θ
JT
= 0.212 ° C/W. If the temperature of the top of the case,
T
C
, and the Power in and out of the device are known, the junction temperature can be calculated by:
T
J
= T
C
+ ( θ
JT
× (P
IN
- P
O
) )
See the Texas Instruments application report PowerPad™ Thermally Enhanced Package (literature number
SLMA002B) for more information regarding the proper use of the PowerPAD package. Also, see the Texas
Instruments application report IC Package Thermal Metrics (literature number SPRA953A) for information
regarding thermal metrics such as θ
JT
.
Because the TAS5602 is a class-D amplifier that switches at a high frequency, the layout of the printed-circuit
board (PCB) should be optimized according to the following guidelines for the best possible performance.
• Decoupling capacitors — The high-frequency 0.1- µ F decoupling capacitors should be placed as close to the
PVCC and AVCC terminals as possible. The BYPASS capacitor and VCLAMP_XX capacitors should also be
placed as close to the device as possible. Large (220- µ F or greater) bulk power-supply decoupling capacitors
should be placed near the TAS5602 on the PVCCx terminals. For single-ended operation, a 220 µ F capacitor
should be placed on each PVCC pin. For Bridge-tied operation, a single 220 µ F, capacitor can be shared
between A and B or C and D.
• Grounding — The AVCC decoupling capacitor and BYPASS capacitor should each be grounded to analog
ground (AGND). The PVCCx decoupling capacitors and VCLAMP_xx capacitors should each be grounded to
power ground (PGND). Analog ground and power ground should be connected at the thermal pad, which
should be used as a central ground connection or star ground for the TAS5602.
• Output filter — The reconstruction LC filter should be placed as close to the output terminals as possible for the
best EMI performance. The capacitors should be grounded to power ground.
• Thermal pad — The thermal pad must be soldered to the PCB for proper thermal performance and optimal
reliability. The dimensions of the thermal pad and thermal land are described in the mechanical section at the
back of the data sheet. See TI Technical Briefs SLMA002 and SLOA120 for more information about using the
thermal pad. For recommended PCB footprints, see figures at the end of this data sheet.
For an example layout, see the TAS5602 Evaluation Module (TAS5602EVM) User Manual, (SLOU189 ). Both the
EVM user manual and the thermal pad application note are available on the TI Web site at http://www.ti.com .
This section focuses on methods that use the basic equipment listed below:
• Audio analyzer or spectrum analyzer
• Digital multimeter (DMM)
• Oscilloscope
• Twisted-pair wires
• Signal generator
• Power resistor(s)
• Linear regulated power supply
• Filter components
• EVM or other complete audio circuit
Figure 23 shows the block diagrams of basic measurement systems for class-AB and class-D amplifiers. A sine
wave is normally used as the input signal because it consists of the fundamental frequency only (no other
harmonics are present). An analyzer is then connected to the audio power amplifier (APA) output to measure the
voltage output. The analyzer must be capable of measuring the entire audio bandwidth. A regulated dc power
supply is used to reduce the noise and distortion injected into the APA through the power pins. A System Two™
audio measurement system (AP-II) by Audio Precision™ includes the signal generator and analyzer in one
package.
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Product Folder Link(s): TAS5602