SLOS406A − FEBRUARY 2003 − REVISED MARCH 2003
25
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APPLICATION INFORMATION
thermal considerations: output power and maximum ambient temperature (continued)
Example. What is the maximum ambient temperature for an application that requires the TPA3003D2 to drive
3 W into an 8-
Ω
speaker (stereo)?
P
Dissipated
= 6 W x ((1 / 0.75) – 1) = 2 W
(P
O
= 3 W * 2)
T
Amax
= 150
°
C – (45
°
C/W x 2 W) = 60
°
C
This calculation shows that the TPA3003D2 can drive 3 W of continuous RMS power per channel into an 8-
Ω
speaker up to an ambient temperature of 60
°
C.
printed circuit board (PCB) layout
Because the TPA3003D2 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.
D
Decoupling capacitors — As described on page 23, the high-frequency 0.1-uF decoupling capacitors
should be placed as close to the PVCC (pin 14, 15, 22, 23, 38, 39, 46, 47) and AV
CC
(pin 33) terminals as
possible. The V2P5 (pin 4) capacitor, AV
DD
(pin 29) capacitor, and VCLAMP (pins 25, 36) capacitor should
also be placed as close to the device as possible. Large (10 uF or greater) bulk power supply decoupling
capacitors should be placed near the TPA3003D2 on the PVCCL, PVCCR, and AV
CC
terminals.
D
Grounding — The AV
CC
(pin 33) decoupling capacitor, AV
DD
(pin 29) capacitor, V2P5 (pin 4) capacitor,
COSC (pin 28) capacitor, and ROSC (pin 27) resistor should each be grounded to analog ground (AGND,
pin 26. The PVCC (pin 9 and pin 16) decoupling capacitors should each be grounded to power ground
(PGND, pins 18, 19, 42, 43). Basically, an AGND island should be created with a single connection to PGND.
D
Output filter — The ferrite EMI filter (Figure 25, page 18) should be placed as close to the output terminals
as possible for the best EMI performance. The LC filter (Figure 24, page 18 should be placed close to the
outputs. The capacitors used in both the ferrite and LC filters should be grounded to PGND.
For an example layout, please refer to the TPA3003D2 Evaluation Module (TPA3003D2EVM) User Manual, TI
literature number SLOU159. The EVM user manual is available on the TI web site at http://www.ti.com.
basic measurement system
This section focuses on methods that use the basic equipment listed below:
D
Audio analyzer or spectrum analyzer
D
Digital multimeter (DMM)
D
Oscilloscope
D
Twisted pair wires
D
Signal generator
D
Power resistor(s)
D
Linear regulated power supply
D
Filter components
D
EVM or other complete audio circuit
Summary of Contents for TPA3003D2
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