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Description
The PAM8403H is a 3W, class-D audio amplifier. It offers low THD+N,
allowing it to achieve high quality sound reproduction. The new
filterless architecture allows the device to drive the speaker directly,
requiring no low-pass output filters, thus saving system cost and PCB
area.
With the same numbers of external components, the efficiency of the
PAM8403H is much better than that of class-AB cousins. It can
extend the battery life, ideal for portable applications.
The PAM8403H is available in SOP-16 package.
Features
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PAM8403H
FILTERLESS 3W CLASS-D STEREO AUDIO AMPLIFIER
Pin Assignments
3W Output at 10% THD with a 4 Load and 5V Power Supply
Filterless, Low Quiescent Current and Low EMI
Low THD+N
Superior Low Noise
Efficiency up to 90%
Short Circuit Protection
Thermal Shutdown
Few External Components to Save the
Space and Cost
Pb-Free Package
Applications
LCD Monitors / TV Projectors
Notebook Computers
Portable Speakers
Portable DVD Players, Game Machines
Cellular Phones/Speaker Phones
PAM8403H
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Typical Applications Circuit
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PAM8403H
Pin Descriptions
Pin Number Pin Name Function
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
-OUT_L
PGND
+OUT_L
PVDD
MUTE
VDD
INL
VREF
NC
INR
GND
SHDN
PVDD
+OUT_R
PGND
-OUT_R
PAM8403H
Document number: DSxxxxx Rev. 1 - 0
Left Channel Negative Output
Power GND
Left Channel Positive Output
Power V
Mute Control Input（active low）
Analog V
Left Channel Input
Internal analog reference, connect a bypass capacitor from VREF to GND
No connected
Right Channel Input
Analog GND
Shutdown Control Input (active low)
Power V
Right Channel Positive Output
Power GND
Right Channel Negative Output
DD
DD
DD
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Functional Block Diagram
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PAM8403H
Absolute Maximum Ratings (@T
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.
Parameter Rating Unit
Supply Voltage Range 6.0
Input Voltage
Operation Temperature Range -40 to +85
Maximum Junction Temperature 150
Operation Junction Temperature -40 to +125
Storage Temperature -65 to 150
Soldering Temperature 300, 5sec
Recommended Operating Conditions (@T
Parameter Rating Unit
Supply Voltage Range 2.5 to 5.5 V
Operation Temperature Range -40 to +85 °C
Junction Temperature Range -40 to +125 °C
PAM8403H
Document number: DSxxxxx Rev. 1 - 0
= +25°C, unless otherwise specified.)
A
-0.3 to V
+0.3
DD
= +25°C, unless otherwise specified.)
A
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V
°C
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PAM8403H
Thermal Information
Parameter Package Symbol Max Unit
Thermal Resistance (Junction to Ambient) SOP-16
Thermal Resistance (Junction to Case) SOP-16
Internal Power Dissipation (@ TA = +25°C)
Note: 1. The maximun output current for SOT23-5 package is limited by internal power dissipation capacity as described in
Application Information here inafter.
SOP-16
PD
JA
JC
Electrical Characteristics (@T
= +25°C, VDD = 5V, Gain = 24dB, RL = 8, unless otherwise specified.)
A
Symbol Parameter Test Conditions Min Typ Max Units
VIN
PO
Supply Voltage 2.5 5.5 V
= 4 V
L
Output Power
THD+N = 10%,f = 1kHz , R
THD+N =1%, f = 1kHz, RL = 4 V
THD+N =10%,f = 1kHz, RL = 8 V
THD+N = 1%, f = 1kHz, RL = 8 V
V
= 5.0V,PO = 0.5W, RL = 8
THD+N
GV
PSRR
CS
Total Harmonic Distortion
Plus Noise
Gain 23 24 25 dB
Power Supply Ripple
Rejection
Crosstalk
SNR Signal-to-Noise Ration
VN
IQ
I
MUTE
ISD
VOS
VIH
VIL
VIH
VIL
Output Noise
Quiescent Current
Muting Current
Shutdown Current
Output Offset Voltage
Enable Input High Voltage
Enable Input LowVoltage
MUTE Input High Voltage
MUTE Input Low Voltage
DD
VDD = 5.0V, PO = 1W, RL = 4
V
= 5.0V, Inputs AC-grounded with
DD
= 0.47F
C
IN
VDD = 5V, PO = 0.5W, RL = 8, GV = 20dB
V
= 5V, V
DD
= 5V, Inputs AC-Grounded with
V
DD
= 0.47F
C
IN
= 1V,GV = 20dB
ORMS
VDD = 5.0V
VDD = 5.0V V
VDD = 2.5V to 5.5V V
VIN = 0V, VDD = 5V
VDD = 5.0V
VDD = 5.0V
VDD = 5.0V
VDD = 5.0V
PAM8403H
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110
23
°C/W
90 mW
= 5.0V
DD
= 5.0V
DD
= 5.0V
DD
= 5.0V
DD
2.85 3.20 W
2.25 2.50 W
1.5 1.8 W
1.2 1.4 W
f = 1kHz 0.15 0.20 %
f = 1kHz 0.15 0.20 %
f = 100Hz -59 -50 dB
f = 1kHz -58 -50 dB
f = 1kHz -95 -80 dB
f = 1kHz 74 80 dB
A-weighting 100 200
No A-weighting 150 300 µV
No load 16 20 mA
MUTE
SD
= 0.3V
= 0.3V
8 12 mA
20 µA
10 mV
1.5 V
0.4 V
1.5 V
0.4 V
November 2012
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Typical Performance Characteristics (@T
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= +25°C, unless otherwise specified.)
A
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PAM8403H
PAM8403H
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Typical Performance Characteristics (cont.) (@T
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= +25°C, unless otherwise specified.)
A
PAM8403H
PAM8403H
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PAM8403H
Application Information
1. When the PAM8403H works with LC filters, it should be connected with the speaker before it's powered on, otherwise it will be damaged
easily.
2. When the PAM8403H 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.
3. The recommended operating voltage is 5.5V. When the PAM8403H is powered with four battery cells, it should be noted that the voltage of
four new dry or alkaline batteries is over 6.0V, higher than its operation voltage, which will probably damage the device. Therefore, it's
recommended to use either four Ni-MH (Nickel Metal Hydride) rechargeable batteries or three dry or alkaline batteries.
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 because of the big gain of the PAM8403H.
5. When testing the PAM8403H 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.
Test Setup for Performance Testing
Notes: 1. The Audio Precision(AP) AUX-0025 low pass filter is necessary for class-D amplifier measurement with AP analyzer.
2. Two 22H inductors are used in series with load resistor to emulate the small speaker for efficiency measurement.
Maximum Gain
As shown in block diagram (Page 2), the PAM8403H has two internal amplifier stages. The first stage's gain is externally configurable, while the
second stage's is internally fixed. The closed-loop gain of the first stage is set by s electing the ratio of RF to RI while the second sta ge's gain is
fixed at 2x.The output of amplifier 1 serves as the input to amplifier 2, thus the t wo amplifiers produce signals identical in magnitude, bu t different
in phase by 180°. Consequently, the differential gain for the IC is
A
The PAM8403H sets maximum R
= 20*log [2*(RF/RI)]
VD
= 142k, minimum RI = 18k, so the maximum closed-gain is 24dB.
F
Mute Operation
The MUTE pin is an input for controlling the output state of the PAM8403H. A logic low on this pin disables the outputs, and a logic high on this
pin enables the outputs. This pin may be used as a quick disable or enable of the outputs without a volume fade. Quiescent current is listed in
the electrical characteristic table. The MUTE pin can be left floating due to the internal pull-up.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8403H contains shutdown circuitry to turn off the amplifier's bias circuitry. This
shutdown feature turns the amplifier off when logic low is applied to the SHDN pin. By switching the SHDN pin connected to GND, the
PAM8403H supply current draw will be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up.
PAM8403H
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PAM8403H
Application Information (cont.)
Power Supply Decoupling
The PAM8403H is a high performance CMOS audio amplifier that requires adequate power supp ly 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 frequenc y transients, spikes, or digital hash on the line,
a good low equivalent-seriesresistance (ESR) ceramic capacitor, typically 1.0F, works best, placing it as close as possible to the device V
terminal. For filtering lowerfrequency noise signals, a large capacitor of 20F (ceramic) or greater is recomm ended, placing it near the audio
power amplifier.
Input Capacitor (CI)
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 attenuation. 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 s ystem performance. In t his case, input
capacitor (C
In addition to system cost and size, click and pop performance is affected by the size of the input coupling capacitor, C
capacitor requires more charge to reach its quiescent DC voltage (nominally 1/2 V
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.
Analog Reference Bypass Capacitor (C
The Analog Reference Bypass Capacitor (C
from shutdown mode, C
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 (CBYP) with values of 0.47F to 1.0F 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.
) and input resistance (RI) of the amplifier form a high-pass filter with the corner frequency determined by equation below,
I
1
f
C
R2
C
I
I
. A larger input coupling
I
). This charge comes from the internal circuit via the
DD
)
BYP
) is the most critical capacitor and serves several important functions. During start-up or recovery
BYP
determines the rate at which the amplifier starts up. The second function is to reduce noise caused b y the power
BYP
Under Voltage Lock-Out (UVLO)
The PAM8403H incorporates circuitry designed to detect low supply voltage. When the supply voltage drops to 2.0V or below, the PAM8403H
outputs are disabled, and the device comes out of this state and starts to normal function when V
2.2V.
DD
Short Circuit Protection (SCP)
The PAM8403H has short circuit protection circuitry on the outputs to prevent damage to the device when output-to-output or out put-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 PAM8403H prevents the device from damage when the internal die temperature exceeds 140°C. Ther e is a 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 b y 30°C. This large hystereis will prevent motor
boating sound well and the device begins normal operation at this point without extrenal system intervention.
DD
PAM8403H
Document number: DSxxxxx Rev. 1 - 0
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Application Information (cont.)
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 1MHz and higher. When selecting a
ferrite bead, choose one with high impedance at high frequencies, and low impedance at low frequencies.
Figure 2. Ferrite Bead Filter to Reduce EMI
Ordering Information
Part Number Part Marking Package Type Standard Package
PAM8403DR-H
PAM8403H
Document number: DSxxxxx Rev. 1 - 0
PAM8403
XXXYWWLL
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SOP-16 2500 Units/Tape&Reel
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Marking Information
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PAM8403H
Package Outline Dimensions (All dimensions in mm.)
SOP-16
PAM8403H
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Copyright © 2012, Diodes Incorporated
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IMPORTANT NOTICE
LIFE SUPPORT
PAM8403H
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