PAM8610
10W Stereo Class-D Audio Power Amplifier with DC Volume Control
Test Setup for Performance Testing
PAM8610 Demo Board
Load
AP
+OUT
Input
Low Pass
AP System One
Analyzer
AP System One
Generator
Filter
-OUT
GND
AUX-0025
VDD
Power Supply
Notes
1. The AP AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer.
2. Two 22μH inductors are used in series with load resistor to emulate the small speaker for efficiency
measurement.
Application Information
Power and Heat Dissipation
If the rated workable junction temperature is
150°C, the relationship between ambient
temperature and permitted Ploss is shown in below
diagram.
Choose speakers that are able to stand large
output power from the PAM8610. Otherwise,
speaker may suffer damage.
10
9
8
7
6
5
4
3
2
1
0
Heat dissipation is very important when the
device works in full power operation. Two factors
affect the heat dissipation, the efficiency of the
device that determines the dissipation power, and
the thermal resistance of the package that
determines the heat dissipation capability.
In operation, some of power is dissipated to the
resistors.
Power Dissipation: Ploss=(Po*(1-η)/η)*2
0
20
40
60
80
100
The PAM8610’s efficiency is 90% with 10W ouput
and 8Ω load. The dissipation power is 2.22W.
Ta
Thermal resistance of junction to ambient of the
QFN package is 18.1°C/W and the junction
temperature Tj=Ploss*θjA+Ta, where Ta is ambient
temperature. If the ambient temperature is 85°C,
the QFN’s junction temperature
From the diagram, it can be found that when the
device works at 10W/8Ω load the dissipation
power is 1.1W per channel, 2.2W total, the
permitted ambient temperature is over 100°C.
This is proven by actual test. The PAM8610 can
work in full output power under 85°C ambient
temperature.
Tj=2.22*18.1+85=125°C
which is lower than 150°C rated junction
temperature.
Power Analog Microelectronics,Inc
www.poweranalog.com
08/2008 Rev 1.2
12
PAM [ POWER ANALOG MICOELECTRONICS ]
