PAM PAM8003

PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Key Features
General Description
n
2.5W Output at 10% THD with a 4Ω Load
and 5V Power Supply
n
3W Output at 10% THD with a 3Ω Load and
5V Power Supply
n
Filterless, Low Quiescent Current and Low
EMI
n
Low THD+N
n
64-step DC Volume Control
n
Superior Low Noise
n
Short Circuit Protection
n
Thermal Shutdown
n
Few External Components to Save the
Space and Cost
n
RoHS Pass and Green Package
The PAM8003 is a 2.5W, class-D audio amplifier.
It offers low THD+N, allowing it to achieve highquality sound reproduction. The new filterless
architecture allows the device to drive the speaker
directly, requiring no low-pass output filters, thus
to save the system cost and PCB area.
With the same numbers of external components,
the efficiency of the PAM8003 is much better than
that of class-AB cousins. It can extend the battery
life, ideal for portable applications.
The PAM8003 is available in SOP-16L package.
Applications
n
LCD Monitors / TV
n
Notebook Computers
n
Portable Speakers
n
Portable DVD Players, Game Machines
Typical Application
VDD
PVDD
1µF
Ri
INL
INL
+OUTL
VREF
-OUTL
PAM8003
1µF
0.47µF
INR
Ri
-OUTR
INR
VOLUME
SHDN
SHDN
1µF
PVDDL PVDDR
VDD
0.47µF
10µF
1µF
+OUTR
SHDN
GND PGNDL PGNDR
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07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Block Diagram
VDD
PVDDR PGNDR
VDD/2
+
-
INR
+
-
+OUTR
DRIVER
-OUTR
MODULATOR
VOLUME
ATTENUATION DECODER
INTERFACE CONTROL
SHDN
THERMAL
PROTECTION
BIAS AND
REFERENCES
INTERNAL
OSCILLATOR
OSC
CURRENT
PROTECTION
MODULATOR
-
INL
+
VDD/2
VREF
+OUTL
DRIVER
-
-OUTL
+
GND
PVDDL
PGNDL
Pin Configuration & Marking Information
Top View
SOP-16
16 PVDDR
15 -OUTR
14 PGNDR
13 +OUTR
PAM8003
XATYWWLL
PVDDL 1
-OUTL 2
PGNDL 3
+OUTL 4
SHDN 5
VREF 6
INL 7
GND 8
12
11
10
9
VOLUME
NC
INR
VDD
X: Internal Code
A: Assembly Code
T: Testing Code
Y: Year
WW: Week
LL: Internal Code
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PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Pin Descriptions
Pin Number
Pin Name
Description
1
PVDDL
Left Channel Power Supply
2
-OUTL
Left Channel Negative Output
3
PGNDL
Left Channel Power GND
4
+OUTL
Left Channel Positive Output
5
SHDN
Shutdown Control Input(active low)
6
VREF
Internal analog reference, connect a bypass capacitor from VREF to GND
7
INL
8
GND
Analog Ground
9
VDD
Analog Power Supply
10
INR
Right Channel Input
11
NC
No Connected
12
VOLUME
13
+OUTR
Right Channel Positive Output
14
PGNDR
Right Channel Power GND
15
-OUTR
Right Channel Negative Output
16
PVDDR
Right Channel Power Supply
Left Channel Input
DC volume control to set the gain of Class-D
Absolute Maximum Ratings
These are stress ratings only and functional operation is not implied. Exposure to absolute
maximum ratings for prolonged time periods may affect device reliability. All voltages are with
respect to ground.
Supply Voltage............................................6.0V
Input Voltage.............................-0.3V to V DD+0.3V
Maximum Junction Temperature..................150°C
Storage Temperature.....................-65 °C to 150 °C
Soldering Temperature....................... 300°C, 5sec
Recommended Operating Conditions
Supply voltage Range........................ 2.5V to 5.5V
Operation Temperature Range.........-40 °C to 85 °C
Junction Temperature Range.........-40 °C to 125 °C
Thermal Information
Parameter
Symbol
Package
Maximum
Unit
Thermal Resistance (Junction to Ambient)
θJA
SOP-16L
110
°C/W
Thermal Resistance (Junction to Case)
θJC
SOP-16L
23
°C/W
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PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Electrical Characteristic
V DD=5V, Gain=24dB, R L=8Ω, T A=25 °C , unless otherwise noted.
Symbol
Parameter
VIN
Supply Power
Po
Test Conditions
MIN
2.5
2.75
W
THD+N=1%,f=1kHz, RL=4 Ω
VDD=5.0V
2.2
W
THD+N=10%,f=1kHz, RL=8 Ω
VDD=5.0V
1.65
W
THD+N=1%,f=1kHz, RL=8 Ω
VDD=5.0V
1.3
W
Total Harmonic Distortion Plus
VDD=3.6V,Po=0.5W,RL=8 Ω
Noise
VDD=5.0V,Po=1W,RL=4 Ω
Power Supply Ripple Rejection
Cs
Crosstalk
SNR
Signal-to-noise ratio
Vn
Output noise
0.16
f=1kHz
VDD=5.0V, Inputs ac-grounded with
0.17
f=1kHz
Quiescent Current
Rdson
Shutdown Current
Static Drain-to-source On-state
Resistor
%
0.26
f=1kHz
-70
dB
VDD=5V,Po=0.5W,RL=8Ω,Gv=20dB
F=1kHz
-93
dB
VDD=5V, Gv=6dB
f=1kHz
86
dB
VDD=5V, Inputs ac-grounded with
A-weighting
33
CIN=0.47µF,Gv=6dB
No A-weighting
50
CIN=0.47µF,Gv=6dB
RL=8Ω, THD=10%
Efficiency
%
0.12
µV
87
f=1kHz
%
RL=4Ω, THD=10%
79
VDD=5.0V
4.5
7
4
6.5
3.7
5.5
No load
VDD=3.6V
VDD=3.0V
ISD
V
Output Power
PSRR
IQ
5.5
VDD=5.0V
VDD=3.6V,Po=1W,RL=4 Ω
η
MAX UNIT
THD+N=10%,f=1kHz, RL=4 Ω
VDD=5.0V,Po=0.5W,RL=8 Ω
THD+N
TYP
VDD=2.5V to 5.5V
1
IDS=500mA,Vgs=5V
PMOS
0.41
NMOS
0.27
mA
µA
mΩ
fsw
Switching Frequency
VDD=3V to 5V
210
kHz
Vos
Output Offset Voltage
Vin=0V, VDD=5V
10
mV
VIH
Enable Input High Voltage
VDD=5.0V
VIL
Enable Input Low Voltage
VDD=5.0V
OTP
Over Temperature Protection
OTH
Over Temperature Hysterisis
1.5
No Load, Junction Temperature
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4
V
0.4
VDD=5V
150
°C
30
联系人:熊伟
07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Typical Operating Characteristics (T =25°C)
A
AudioPrecision
07/12/1018:50:03
1. THD+N vs Output Power
30
T
T
T
A ud io Precision
30
T T
20
20
R L=4Ω
R L=8Ω
10
10
5
5
V DD=3.6V
2
V DD=3.6V
2
%
%
1
1
V DD=5V
V DD=5V
0.5
0.5
0.2
0.2
0.1
1m
2m
5m
10m
20m
50m
100m
200m
500m
1
2
0.1
1m
3
2m
5m
1 0m
20m
5 0m
AudioPrecision
07/13/1010:09:45
3. THD+N vs Frequency
10
5
T
AudioPrecision
20 0m
500m
1
2
3
07/13/1009:56:36
4. THD+N vs Frequency
10
T
R L=4Ω
Po=0.5W
R L=8Ω
Po=0.5W
5
2
2
1
1
%
%
0.5
0.5
R
R
0.2
L
0.1
0.06
20
50
100
200
500
1k
0.2
L
0.1
2k
5k
10k
0.06
20
20k
50
100
200
500
AudioPrecision
07/13/1010:14:11
5. Frequency Response
AudioPrecision
+25
-50T
+24.5
-55
+24
-60
+23.5
-65
+23
d
B
g +22.5
+21
+20.5
+20
10
2k
5k
10k
20k
T
07/13/1012:02:45
6. Crosstalk
T T T T
T
Gain=24dB
R L=4Ω
Vo=0.1Vrms
Cin=1uF
-70
d
B
+22
+21.5
1k
Hz
Hz
A
100m
W
W
07 /12 /10 1 8:2 0:57
2. THD+N vs Output Power
-75
-80
VDD=5V
Gain=24dB
R L=4Ω
Vo=0.1Vrms
Cin=1uF
20
50
L to R
-85
-90
-95
100
200
500
1k
2k
5k
10k
20k
-100
20
R to L
50
100
200
500
1k
2k
5k
10k
20k
Hz
Hz
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07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Typical Operating Characteristics (continued)
AudioPrecision
-20
AudioPrecision
07/13/1014:11:35
7. PSRR
-50
TT TTT
-55
VDD=5V
Vpp=200mV
Gain=6dB
R L=4Ω
-25
-30
-35
-60
-65
-70
-75
-40
-45
d
B
07/12/1019:15:27
8. FFT noise
d
B
r
-80
A
-90
-85
-50
-55
-95
-60
-100
-105
-65
-110
-70
-115
-75
10
20
50
100
200
500
1k
2k
5k
10k
20k
50k
-120
20
100k
50
100
200
500
Hz
1k
2k
5k
10k
20k
Hz
9. Efficiency
10.Rdson VS Load Current
100
600
90
500
80
RDS(ON)(ohm)
60
50
40
30
20
4ohm
10
8ohm
400
300
200
PMOS
100
NMOS
0
0
0
500
1000
1500
2000
Output Power(m W)
2500
3000
0
500
11. Quiescent Current
1000
Load Current(m A)
1500
2000
5
6
12. Switching Frequency
6
220
5
215
210
4
Fsw(kHz)
Quiescent Current(mA)
Efficiency(%)
70
3
205
200
2
195
1
190
0
185
2
3
4
Input Votage(V)
5
6
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2
3
4
Input Voltage(V)
联系人:熊伟
07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Table 1. DC Volume Control
STEP
Gain (dB)
STEP
Gain (dB)
0
-75
32
11.6
1
-40
33
12
2
-34
34
12.4
3
-28
35
12.8
4
-22
36
13.2
5
-16
37
13.6
6
-10
38
14
7
-7.5
39
14.4
8
-5
40
14.8
9
-2.5
41
15.2
10
0
42
15.6
11
1.5
43
16
12
3
44
16.4
13
4
45
16.8
14
4.4
46
17.2
15
4.8
47
17.6
16
5.2
48
18
17
5.6
49
18.4
18
6
50
18.8
19
6.4
51
19.2
20
6.8
52
19.6
21
7.2
53
20
22
7.6
54
20.4
23
8
55
20.8
24
8.4
56
21.2
25
8.8
57
21.6
26
9.2
58
22
27
9.6
59
22.4
28
10
60
22.8
29
10.4
61
23.2
30
10.8
62
23.6
31
11.2
63
24
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PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
probably damage the device. Therefore, it's
recommended to use either 4 Ni-MH (Nickel
Metal Hydride) rechargeable batteries or 3 dry or
alkaline batteries.
Application Notes
1. When the PAM8003 works with LC filters, it
should be connected with the speaker before it's
powered on, otherwise it will be damaged easily.
4. One should not make the input signal too
large. Large signal can cause the clipping of
output signal when increasing the volume. This
will damage the device b ecause of big gain of the
PAM8003 .
2. When the PAM8003 works without LC filters,
it's better to add a ferrite chip bead at the
outgoing line of speaker for suppressing the
possible electromagnetic interference.
5. When testing the PAM8003 without LC filters
by using resistor instead of speaker as the output
load, the test results, e.g. THD or efficiency, will
be worse than those of using speaker as load.
3. The recommended operating voltage is
5.5V. When the PAM8003 is powered with 4
battery cells, it should be noted that the voltage
of 4 new dry or alkaline batteries is over 6.0V,
higher than its operation voltage, which will
Test Setup for Performance Testing
PAM8003 Demo Board
Load
+OUT
AP System
Generator
Input
AP
Low Pass
Filter
GND
-OUT
AP System
Analyzer
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.
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PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Application Information
Power supply decoupling
The PAM8003 is a high performance CMOS
audio amplifier that requires adequate power
supply decoupling to ensure the output THD and
PSRR as low as possible. Power supply
decoupling affects low frequency response.
Optimum decoupling is achieved by using two
capacitors of different types targeting to different
types of noise on the power supply leads. For
higher frequency transients, spikes, or digital
hash on the line, a good low equivalent-seriesresistance (ESR) ceramic capacitor, typically
1.0µF, works best, placing it as close as possible
to the device V DD terminal. For filtering lowerfrequency noise signals, a large capacitor of
20µF (ceramic) or greater is recommended,
placing it near the audio power amplifier.
Input Capacitor (C i)
Large input capacitors are both expensive and
space hungry for portable designs. Clearly, a
certain sized capacitor is needed to couple in low
frequencies without severe attenu ation. But in
many cases the speakers used in portable
systems, whether internal or external, have little
ability to reproduce signals below 100Hz to
150Hz. Thus, using a large input capacitor may
not increase actual system perfor mance. In this
case, input capacitor (C i) and input resistance
(R i) of the amplifier form a high-pass filter with
the corner frequency determined by equation
below.
In addition to system cost and size, click and pop
perfor mance is affected by the size of the input
coupling capacitor, C i. A larger input coupling
capacitor requires more charge to reach its
quiescent DC voltage (nominally 1/2 V DD). This
charge comes from the internal circuit via the
feedback and is apt to create pops upon device
enable. Thus, by minimizing the capacitor size
based on necessary low frequency response,
turn-on pops can be minimized.
fC=
1
2πRiCi
Analog Reference Bypass Capacitor (C BYP)
from shutdown mode, C BYP determines the rate at
which the amplifier starts up. The second
function is to reduce noise caused by the power
supply coupling into the output drive signal. This
noise is from the internal analog reference to the
amplifier, which appears as degraded PSRR and
THD+N.
A ceramic bypass capacitor (C BYP) with values of
0.1µF to 1.0µF is recommended for the best THD
and noise performance. Increasing the bypass
capacitor reduces clicking and popping noise
from power on/off and entering and leaving
shutdown.
Under Voltage Lock-out (UVLO)
The PAM8003 incorporates circuitry designed to
detect low supply voltage. When the supply
voltage drops to 2.0V or below, the PAM8003
outputs are disabled, and the device comes out
of this state and starts to normal function when
V DD ≥2.2V.
Short Circuit Protection (SCP)
T h e PA M 8 0 0 3 h a s s h o r t c i r c u i t p r o t e c t i o n
circuitry on the outputs to prevent damage to the
device when output-to-output or output-to-GND
short occurs. When a short circuit is detected on
the outputs, the outputs are disabled
immediately. If the short was removed, the
device activates again.
Over Temperature Protection
Thermal protection on the PAM8003 prevents the
device from damage when the internal die
temperature exceeds 140°C. There is a 15
degree tolerance on this trip point from device to
device. Once the die temperature exceeds the
thermal set point, the device outputs are
disabled. This is not a latched fault. The thermal
fault is cleared once the temperature of the die is
reduced by 30°C. This large hysteresis will
prevent motor boating sound well and the device
begins normal operation at this point without
external system intervention.
The Analog Reference Bypass Capacitor (C BYP) is
the most critical capacitor and serves several
important functions. DuAring start-up or recovery
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联系人:熊伟
07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
How to Reduce EMI (Electro Magnetic
Interference)
A simple solution is to put an additional capacitor
1000μF at power supply terminal for power line
coupling if the traces from amplifier to speakers
are short (<20cm).
Most applications require a ferrite bead filter as
shown in Figure 2. The ferrite filter reduces EMI of
around 1 MHz and higher. When selecting a
ferrite bead, choose one with high impedance at
high frequencies, and low impedance at low
frequencies.
Ferrite Bead
OUT+
220pF
Ferrite Bead
OUT220pF
Figure 2: Ferrite Bead Filter to reduce EMI
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07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Ordering Information
PAM8003 X X
Shipping Package
Package Type
Part Number
PAM8003DR
Marking
Package Type
MOQ/Shipping Package
SOP-16L
2,500 Units/Tape&Reel
PAM8003
XATYWWLL
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07/2010 Rev1.0
PAM8003
Filterless 2.5W Class-D Stereo Audio Amplifier
Outline Dimension
A1
A
A2
SOP-16
B
D
E
E1
L
C
θ
e
Symbol
Dimensions Millimeters
Min
Max
A
1.350
1.750
A1
0.100
0.250
A2
1.350
1.550
B
0.330
0.510
C
0.190
0.250
D
9.800
10.000
E
3.800
4.000
E1
5.800
6.300
e
1.270(TYP)
L
0.400
1.270
θ
0º
8º
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07/2010 Rev1.0