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Description
The PAM8007 is a 3W, Class-D audio amplifier with headphone
amplifier. Advanced 64-Step DC volume control minimizes external
components and allows speaker volume control and headphone
volume control. It offers low THD+N, to produce high-quality sound
reproduction. The new filterless architecture allows the device to drive
the speaker directly, without low-pass output filters which will save
30% system cost and 75% PCB area.
With the same numbers of external components, the efficiency of the
PAM8007 is much better than class-AB cousins. It can extend the
battery life thus be ideal for portable applications.
The PAM8007 is available in a SSOP-24 and SOP-24 package.
Features
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PAM8007
FILTERLESS 3W CLASS-D STEREO AUDIO AMPLIFIER
with DC VOLUME CONTROL and HEADPHONE OUTPUT
Pin Assignments
• 3W Output at 10% THD with a 4Ω Load and 5V Power Supply
• Filterless, Low Quiescent Current and Low EMI
• Low THD+N
• 64-Step DC Volume Control
• Headphone Output Function
• Superior Low Noise
• Low Pop Noise
• Efficiency Up to 92%
• 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
• VoIP/Speaker Phones
PAM8007
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Typical Applications Circuit
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PAM8007
Pin Descriptions
Pin
Number
1 -OUT_L Left Channel Negative Output
2 PGNDL Left Channel Power GND
3 PGNDL Left Channel Power GND
4 +OUT_L Left Channel Positive Output
5 PVDDL Left Channel Power Supply
6 MUTE Mute Control Input (active low)
7 VDD Analog VDD
8 INL Left Channel Input
9 EAR INL Left Earphone Input
10 VDC Analog Reference for Gain Control Section
11 VOLUME DC Volume Control to Set the Gain of Class-D
12 EAR OUT L Left Earphone Output(Non-Inverting)
13 EAR OUT R Right Earphone Output(Non-Inverting)
14 VREF Internal Analog Reference, connect a bypass capacitor from VREF to GND
15 LINE/EAR Line / Earphone Switch. Speaker Output (active low), Earphone Output (active high)
16 EAR LN R Right Earphone Input
17 INR Right Channel Input
18 GND Analog GND
19 SHDN Shutdown Control Input (active low)
20 PVDDR Right Channel Power Supply
21 +OUT_R Right Channel Positive Output
22 PGNDR Right Channel Power GND
23 PGNDR Right Channel Power GND
24 -OUT_R Right Channel Negative Output
PAM8007
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Name
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Function
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Functional Block Diagram
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PAM8007
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 6.0
Input Voltage
Maximum Junction Temperature 150
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
Ambient Operation Temperature Range -20 to +85 °C
Junction Temperature Range -20 to +125 °C
PAM8007
Document number: DSxxxxx Rev. 1 - 2
= +25°C, unless otherwise specified.)
A
-0.3 to V
+0.3
DD
= +25°C, unless otherwise specified.)
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V
°C
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PAM8007
Thermal Information
Parameter Package Symbol Max Unit
= 8Ω
= 200mV
PP
= 200mV
PP
90
32
°C/W
2.5 5.5 V
12 16 mA
Ω
1.55 1.75
2.85 3.1
0.12
0.15
W
%
63 dB
-88 dB
85 92 %
80 88 %
µV
69 mW
0.04 %
73 dB
95 dB
µV
8 12 mA
20 µA
V
V
V
October 2012
© Diodes Incorporated
Thermal Resistance (Junction to Ambient)
Thermal Resistance (Junction to Case)
SSOP-24
SOP-24 79.2
SSOP-24
SOP-24 27
θ
JA
θ
JC
Electrical Characteristics (@T
= +25°C, VDD = 5V, Gain = 24dB, RL = 8Ω, unless otherwise specified.)
A
Parameter Symbol Test Conditions Min Typ Max Units
Class D Stage
Supply Voltage Range
Quiescent Current
Output Offset Voltage
Drain-Source On-State Resistance
Output Power
Total Harmonic Distortion Plus Noise
V
I
V
R
DS(ON)
P
THD+N
Power Supply Ripple Rejection PSRR
Channel Separation CS
Oscillator Frequency
f
OSC
Efficiency η
Noise
V
DD
No Load
Q
No Load 10 50 mV
OS
IDS = 0.5A
THD+N = 10%
O
f = 1kHz
R
R
= 8Ω, PO = 1W, f = 1KHz
L
= 4Ω, PO = 2W, f = 1KHz
L
P MOSFET 0.23
N MOSFET 0.17
R
L
RL = 4Ω
Input AC-GND, f = 1KHz, V
V
= 1V
O
200 250 300 kHz
P
= 1.75W, f =1 kHz, RL = 8Ω
O
, f = 1KHz
RMS
PO = 3.0W, f =1 kHz, RL = 4Ω
N
Input AC-GND
Gain = 12dB
A-Weighting 65
No A-Weighting 90
Signal Noise Ratio SNR f = 20 – 20kHz, THD = 1% 84 dB
Earphone Stage
Output Power
Total Harmonic Distortion Plus Noise THD+N
Power Supply Ripple Rejection PSRR
Channel Separation CS
Noise
P
THD+N = 1%, RL = 32Ω, f = 1kHz
O
R
= 32Ω, PO = 10mW, f = 1kHz
L
Input AC-GND, f = 1kHz, V
V
= 1V
O
V
Input
N
AC-GND
, f = 1kHz
RMS
A-Weighting 19
No A-Weighting 25
Signal Noise Ratio SNR f = 20 – 20kHz, THD = 1% 97 dB
Control Section
Mute Current
Shutdown Current
SHDN Input High
SHDN Input Low
MUTE Input High
MUTE Input Low
Line/Ear Input High
Line/Ear Input Low
I
MUTE
I
SHDN
V
V
V
V
V
V
SH
SL
MH
ML
DH
DL
V
V
= 0V
MUTE
= 0V
SHDN
1.5
0.4
1.5
0.4
2.5
0.4
Over Temperature Protection OTP 150 °C
Over Temperature Hysteresis OTH 30 °C
PAM8007
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Typical Performance Characteristics (@T
Speaker
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= +25°C, unless otherwise specified.)
A
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PAM8007
PAM8007
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Typical Performance Characteristics (cont.) (@T
Speaker
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= +25°C, unless otherwise specified.)
A
PAM8007
PAM8007
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Typical Performance Characteristics (cont.) (@T
Speaker
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= +25°C, unless otherwise specified.)
A
PAM8007
PAM8007
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Typical Performance Characteristics (cont.) (@T
Earphone Output
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= +25°C, unless otherwise specified.)
A
PAM8007
PAM8007
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Typical Performance Characteristics (cont.) (@T
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= +25°C, unless otherwise specified.)
A
PAM8007
PAM8007
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PAM8007
Typical Performance Characteristics (cont.) (@T
Table 1. DC Volume Control
STEP
1 -80 -80 33 11.6 -9.2
2 -40 -60 34 12.0 -8.6
3 -34 -50 35 12.4 -8.0
4 -28 -40 36 12.8 -7.4
5 -22 -37.7 37 13.2 -6.8
6 -16 -35.4 38 13.6 -6.2
7 -10 -33.1 39 14.0 -5.7
8 -7.5 -30.8 40 14.4 -5.2
9 -5 -28.5 41 14.8 -4.7
10 -2.5 -27.5 42 15.2 -4.2
11 0 -26.4 43 15.6 -3.7
12 1.5 -25.3 44 16.0 -3.2
13 3.0 -24.2 45 16.4 -2.7
14 4.0 -23.1 46 16.8 -2.2
15 4.4 -22.2 47 17.2 -1.8
16 4.8 -21.4 48 17.6 -1.4
17 5.2 -20.6 49 18.0 -1.0
18 5.6 -19.8 50 18.4 -0.6
19 6.0 -19.0 51 18.8 -0.2
20 6.4 -18.2 52 19.2 0.2
21 6.8 -17.4 53 19.6 0.6
22 7.2 -16.6 54 20.0 0.9
23 7.6 -15.9 55 20.4 1.2
24 8.0 -15.2 56 20.8 1.5
25 8.4 -14.5 57 21.2 1.8
26 8.8 -13.8 58 21.6 2.1
27 9.2 -13.1 59 22.0 2.4
28 9.6 -12.4 60 22.4 2.7
29 10.0 -11.7 61 22.8 2.9
30 10.4 -11.0 62 23.2 3.1
31 10.8 -10.4 63 23.6 3.3
32 11.2 -9.8 64 24.0 3.5
Gain (dB)
Class D
PAM8007
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Gain (dB)
Earphone
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= +25°C, unless otherwise specified.)
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STEP
Gain (dB)
Class D
Gain (dB)
Earphone
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PAM8007
Application Information
Mute Operation
The MUTE pin is an input for controlling the output state of the PAM8007. 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 characteristics table. The MUTE pin can be left floating due to the internal pull-up.
For the best power on/off pop performance, the amplifier should be placed in the MUTE mode prior to turning on/off the power
supply.
Shutdown Operation
In order to reduce power consumption while not in use, the PAM8007 contains shutdown circuitry to turn off the amplifier’s bias circuitry. The
amplifier is turned off when logic low is placed on the SHDN pin. By switching the SHDN pin connected to GND, the PAM8007 supply current
draw will be minimized in idle mode. The SHDN pin can be left floating due to the internal pull-up.
Line/Ear Operation
In order to control the speaker/headphone switch, the PAM8007 contains detect circuitry. When line/ear logic low, speaker actice; when logic
high, earphone active.
Power Supply Decoupling
The PAM8007 is a high performance CMOS audio amplifier that requires an adequate power supply decoupling to ensure the output THD and
PSRR are as low as possile. Power supply decoupling affects low frequency on the power supply leads for higher frey response. Optimum
decoupling is achieved by using two capacitors of different types that target different types of noise frequency tranisients, spike, or digital hash
on the line, a good low equivalent-series-resistance (ESR) ceramic capacitor, typically 1.0µF, placed as close as possible to the device V
terminal works best. For filtering lower-frequency noise signals, a large capacitor of 10µF (ceramic) or greater placed near the audio power
amplifier is recommended.
Input Capacitor (CI)
Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certai 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 system performance. In this case,
inout 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 ½ V
feedback and is apt to create pops upon device enable. Thus, by minmizing the capacitor size based on necessary low frequency response,
turn-on pops can be minimized.
Analog Reference Bypass Capacitor (C
Analog Reference Bypass Capacitior (C
from shutdown mode, C
supply caused by coupling into the output device signal. The noise is from the internal analog reference to the amplifier, which appears as
degraded PSRR and THD+N.
A ceramic bypass capacitor (C
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 equation below;
I
1
=
f
C
C
Π
R2
I
I
. A larger inout 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 produced by the power
BYP
) of 0.47µF to 1.0µF is recommended for the best THD and noise performance. Increasing the bypass
BYP
Short Circuit Protection (SCP)
The PAM8007 has short circuit protection circuitry on the outputs that prevents the device from damage when output-to-output and output-to
GND short. When a short circuit is detected on the outputs, the outputs are disabled immediately. If the short was removed, the device
activates again.
PAM8007
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Application Information (cont.)
Over Temperature Protection
Thermal protection on the PAM8007 prevents the device from damage when the internal die temperature exceeds +150°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. The device begins normal operation at this point without external system interaction.
How to Reduce EMI (Elect ro 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 at Figure 1. The ferrite filter reduces EMI around 1MHz and higher. When selecting a
ferrite bead, choose one with high impedance at high frequencies, and low impedance at low frequencies (MH2012HM221-T).
Figure 1. Ferrite Bead Filter to Reduce EMI
PCB Layout Guidelines Grounding
At this stage it is paramount to notice the necessity of separate grounds. Noise currents in the output power stage need to be returned to output
noise ground and nowhere else. Were these currents to circulate elsewhere, they may get into the power supply, the signal ground, etc, worse
yet, they may form a loop and radiate noise. Any of these cases results in degraded amplifier performance. The logical returns for the output
noise currents associated with Class D switching are the respective PGND pins for each channel. The switch state diagram illustrates that
PGND is instrumental in nearly every switch state. This is the perfect point to which the output noise ground trace should return. Also note that
output noise ground is channel specific. A two channel amplifier has two seperate channels and consequently must have two seperate output
noise ground traces. The layout of the PAM8007 offers separate PGND connections for each channel and in some cases each side of the
bridge. Output noise grounds must be tied to system ground at the power in exclusively. Signal currents for the inputs, reference, etc need to be
returned to quite ground. This ground is only tied to the signal components and the GND pin, and GND then tied to system ground.
PCB Layout Example
Figure 2. Top Layer Figure 3. Bottom Layer
PAM8007
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Application Information (cont.)
Test Setup for Performance Testing (Class D)
1. When the PAM8007 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 PAM8007 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 absolute maximum rating of the PAM8007 operation voltage is 6.0V. When the PAM8007 is powered with four battery cells, it should be
noted that the voltage of four new dry or alkaline batteries is over 6V, higher than its maximum operation voltage, which probably make the
device damaged. Therefore, it's recommended to use either four Ni-MH (Nickel Metal Hydride) rechargeable batteries or three dry or alkaline
batteries.
4. The input signal should not be too high, if too high, it will cause the clipping of output signal when increasing the volume. Because the DC
volume control of the PAM8007 has big gain, it will make the device damaged.
5. When testing the PAM8007 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 using speaker as load.
Notes: 1. The Audio Precision (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.
PAM8007
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Ordering Information
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Marking Information
Part Number Package Type Standard Package
PAM8007NHR SSOP-24 2500 Units/Tape&Reel
PAM8007DHR SOP24 1000 Units/Tape&Reel
PAM8007
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Package Outline Dimensions (All dimensions in mm.)
SSOP-24
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PAM8007
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Package Outline Dimensions (cont.) (All dimensions in mm.)
SOP-24
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PAM8007
PAM8007
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes
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application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its patent or
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Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales
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Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and
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indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings
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This document is written in English but may be translated into multiple languages for reference. Only the English version of this document is the
final and determinative format released by Diodes Incorporated.
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without the express
written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the
labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the
failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or systems, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and
any use of Diodes Incorporated products in such safety-critical, life support devices or systems, notwithstanding any devices- or systems-related
information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its
representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or
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Copyright © 2012, Diodes Incorporated
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IMPORTANT NOTICE
LIFE SUPPORT
PAM8007
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