PAM8403DR - Power Analog Microelectronics, Inc.

Key Features

Applications

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

LCD Monitors / TV Projectors

Notebook Computers

Portable Speakers

Portable DVD Players, Game Machines

Cellular Phones/Speaker Phones

directly

system cost

It can extend the battery

life, ideal for portable applications.

General Description

The PAM8403 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

, requiring no low-pass output filters,thus

to save the and PCB area.

With the same numbers of external components,

the efficiency of the PAM8403 is much better than

that of class-AB cousins.

The PAM8403 is available in SOP-16 package.

nPb-Free Package

Typical Application

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

100

0 0.5 1 1.5 2 2.5 3

Output Pow er(W)

Efficiency(%)

RL=8Ω

RL=4Ω

Efficiency vs Output Power

FCC Class B Limit

Radiated Emissions

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

+OUT_L

PGNDPGND

-OUT_L

-OUT_R

+OUT_R

PVDD PVDD

SHDN

VDD

INL

INR

VREF

1μF 1μF 1μF

470μF

VDD PVDD

0.47μF

0.1μF

92 1511

INL

INR

PAM84 03

MUTE

GND

SHDN

MUTE

Block Diagram

Pin Configuration & Marking Information

VDD/2

INTERFACE CONTROL

ATTENUATION DECODER

VDD

INR

MUTE

SHDN

INL

GND

PVDD

PGND

-OUT_L

+OUT_L

VREF

-OUT_R

+OUT_R

PGND

PVDD

MODULATOR

DRIVER

INTERNAL

OSCILLATOR

OSC

BIAS AND

REFERENCES

MODULATOR

DRIVER

THERMAL

PROTECTION

CURRENT

PROTECTION

X: Internal Code

A: Assembly Code

T: Testing Code

Y: Year

WW: Week

LL: Internal Code

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

Top View

SOP-16

PAM8403

XATYWWLL

www.poweranalog.com

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

Pin Descriptions

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 ...........................................6.6V

Operation Temperature Range.........-40°C to 85

Operation Junction Temperature.....-40 to 125

Storage Temperature.....................-65 to 150

Soldering Temperature.......................

Input Voltage.............................-0.3V to V +0.3V

°C

Maximum Junction Temperature..................150°C

°C °C

300°C, 5sec

Recommended Operating Conditions

Supply voltage Range........................ Operation Temperature Range.........-40 to 85

Junction Temperature Range.........-40 to 125

2.5V to 5.5V

Max. Supply Voltage (for Max. duration of

30 minutes)................................................6.4V

°C °C

Thermal Information

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Parameter Symbol Package Maximum Unit

Thermal Resistance (Junction to Ambient) θJA SOP-16 110 °C/W

Thermal Resistance (Junction to Case) θJC SOP-16 23 °C/W

Pin Number Pin Name Description

1 +OUT_L Left Channel Positive Output

2 PGND Power GND

3 -OUT_L Left Channel Negative Output

4 PVDD Power VDD

5MUTE Mute Control Input（active low）

6 VDD Analog VDD

7 INL Left Channel Input

8 VREF Internal analog reference, connect a bypass capacitor from VREF to GND

9 NC No connect

10 INR Right Channel Input

11 GND Analog GND

12 SHDN Shutdown Control Input (active low)

13 PVDD Power VDD

14 -OUT_R Right Channel Negative Output

15 PGND Power GND

16 +OUT_R Right Channel Positive Output

Electrical Characteristic

V =5V, Gain=24dB, R =8 , T =25 , unless otherwise noted.

DD L A

Ω°C

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Symbol Parameter Test Conditions MIN TYP MAX UNIT

VIN Supply Power 2.5 5.5 V

VDD=5.0V 3.2

VDD=3.6V 1.6THD+N=10%,f=1kHz, RL=4 Ω

VDD=3.0V 1.3

VDD=5.0V 2.5

VDD=3.6V 1.3

THD+N=1%,f=1kHz, RL=4 Ω

VDD=3.0V 0.85

VDD=5.0V 1.8

VDD=3.6V 0.9

THD+N=10%,f=1kHz, RL=8 Ω

VDD=3.0V 0.6

VDD=5.0V 1.4

VDD=3.6V 0.72

Po Output Power

THD+N=1%,f=1kHz, RL=8 Ω

VDD=3.0V 0.45

VDD=5.0V,Po=0.5W,RL=8 Ω 0.15

VDD=3.6V,Po=0.5W,RL=8 Ω

f=1kHz

0.11

VDD

=5.0V,Po=1W,RL=4 Ω 0.15

THD+N Total Harmonic Distortion Plus

Noise

VDD

=3.6V,Po=1W,RL=4 Ω f=1kHz 0.11 %

Gv Gain 24 dB

f=100Hz -59

PSRR Power Supply Ripple Rejection VDD

=5.0V, Inputs ac-grounded with

CIN =0.47μF f=1kHz -58

Cs Crosstalk VDD=5V,Po=0.5W,RL=8Ω,Gv=20dB F=1kHz -95 dB

SNR Signal-to-noise ratio VDD=5V, Vorms=1V,Gv=20dB f=1kHz 80 dB

A-weighting 100

Vn Output noise VDD=5V, Inputs ac-grounded with

CIN =0.47μF No A-weighting 150

μV

Dyn Dynamic range VDD=5.0V, THD=1% f=1kHz 90 dB

RL=8Ω, THD=10% 87

η Efficiency RL=4Ω, THD=10% f=1kHz 83 %

VDD=5.0V 16

VDD=3.6V 10IQQuiescent Current

VDD=3.0V

No load

Electrical Characteristic (Continued)

V =5V Gain=24dB, R =8 , T =25 , unless otherwise noted.

DD L A

Ω°C

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Symbol Parameter Test Conditions MIN TYP MAX UNIT

IMUTE Muting Current VDD=5.0V VMUTE=0.3V 3.5 mA

ISD Shutdown Current VDD=2.5V to 5.5V Vsd=0.3V <1 μA

PMOS 180

Rdson Static Drain-to-source On-state

Resistor IDS=500mA,Vgs=5V NMOS 140 mΩ

fsw Switching Frequency VDD=3V to 5V 260 kHz

Vos Output Offset Voltage Vin=0V, VDD=5V 10 mV

VIH Enable Input High Voltage VDD=5.0V 1.5 1.4

VIL Enable Input Low Voltage VDD=5.0V 0.7 0.4 V

VIH MUTE Input High Voltage VDD=5.0V 1.5 1.4

VIL MUTE Input Low Voltage VDD=5.0V 0.7 0.4 V

OTP Over Temperature Protection 140

OTH Over Temperature Hysterisis No Load, Junction Temperature VDD=5V 30 °C

Typical Operating Characteristics (T =25°C)

1. THD+N vs Output Power

R =4 , Gain = 24dB, f=1kHz

LΩ

2. THD+N vs Output Power

V=5V

V =2.5V

V =3.3V

3. THD+N vs Frequency

V =5V, R =4 ,Gain = 24dB, Cin=1 F

DD L Ωμ

4. THD+N vs Frequency

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

R =8 , Gain = 24dB, f=1kHz

LΩ

V=5V

V =2.5V

V =3.3V

V =5V, R =8 ,Gain = 24dB, Cin=1 F

DD L Ωμ

0.01

100

0.02

0.05

0.1

0.2

0.5

20m 450m 100m 200m 500m 1 2

0.01

100

0.02

0.05

0.1

0.2

0.5

20m 450m 100m 200m 500m1 2

0.01

100

0.02

0.05

0.1

0.2

0.5

20 20k50 100 200 500 1k 2k 5k 10k

R0.0 1

100

0.0 2

0.0 5

0.1

0.2

0.5

20 20k50 100 200 500 1k 2k 5k 10k

Typical Operating Characteristics (continued)

7. Noise Floor FFT

Inputs ac-ground, V =5V,

DD R =8 ,Cin=1 F

LΩμ

5. Frequency response

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

V =5V, R =8 ,Gain = 24dB, Cin=1 F

DD L Ωμ

+2 2.6

+2 4.4

+2 2.8

+2 3

+2 3.2

+2 3.4

+2 3.6

+2 3.8

+2 4

+2 4.2

10 20k20 50 100 200 500 1k 2k 5k 10k

6. Crosstalk VS Frequency

V=5V,R=4,

DD L ΩGv=24dB, Po=0.5W

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

20 20k50 100 200 500 1k 2k 5k 10k

TTTTTTTTTTTT

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

20 20k50 100 200 500 1k 2k 5k 10k

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 Notes

1. When the PAM8403 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 PAM8403 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 PAM8403 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

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.

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

5. When testing the PAM8403 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.

ecause of big gain of the

PAM8403

Test Setup for Performance Testing

AP System One

Generator

PAM8403 Demo Board

+OUT

Input

Load AP

Low Pass

Filter

AUX-0025

AP System One

Analyzer

GND -OUT

VDD

Power Supply

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Maximum Gain

Mute Operation

As shown in block diagram (page 2), the

PAM8403 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

selecting the ratio of R to R while the second

stage's gain is fixed at 2x.The output of amplifier

1 serves as the input to amplifier 2, thus the two

amplifiers produce signals identical in

magnitude, but different in phase by 180°.

Consequently, the differential gain for the IC is

A =20*log [2*(R /R )]

The PAM8403 sets maximum R =142k ,

minimum R =18k , so the maximum closed-gain

is 24dB.

The pin is an input for controlling the

output state of the PAM8403. 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 pin can

be left floating due to the internal pull-up.

VD f i

MUTE

Shutdown operation

Power supply decoupling

Input Capacitor (C )

Analog Reference Bypass Capacitor (C )

In order to reduce power consumption while not

in use, the PAM8403 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 pin. By switching

the pin connected to GND, the PAM8403

supply current draw will be minimized in idle

mode. The pin can be left floating due to

the internal pull-up.

The PAM8403 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-series-

resistance (ESR) ceramic capacitor, typically

1.0μF, works best, placing it as close as possible

to the device V terminal. For filtering lower-

frequency noise signals, a large capacitor of

20μF (ceramic) or greater is recommended,

placing it near the audio power amplifier.

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 system performance. In this

case, input capacitor (C ) and input resistance

(R ) 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

performance is affected by the size of the input

coupling capacitor, C . A larger input coupling

capacitor requires more charge to reach its

quiescent DC voltage (nominally 1/2 V ). 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.

The Analog Reference Bypass Capacitor (C ) is

the most critical capacitor and serves several

important functions. During start-up or recovery

from shutdown mode, C 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 ) with values of

0.47μF 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.

SHDN

BYP

Application Information

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

2πR C

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Under Voltage Lock-out (UVLO)

Short Circuit Protection (SCP)

How to Reduce EMI (Electro Magnetic

Interference)

The PAM8403 incorporates circuitry designed to

detect low supply voltage. When the supply

voltage drops to 2.0V or below, the PAM8403

outputs are disabled, and the device comes out of

this state and starts to normal function when V

2.2V.

The PAM8403 has short circuit protection

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.

A simple solution is to put an additional capacitor

1000 F 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.

≥

Over Temperature Protection

Thermal protection on the PAM8403 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 . This large hysteresis will prevent motor

boating sound well and the device begins normal

operation at this point without external system

intervention.

Figure 2: Ferrite Bead Filter to reduce EMI

°C

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

220pF

OUT+

OUT-

Ferrite Bead

Ordering Information

PAM8403 X X

Package Type

Shipping Package

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

09/2008 Rev 1.3

,Power Analog Microelectronics Inc

www.poweranalog.com

Part Number Marking Package Type MOQ/Shipping Package

PAM8403DR PAM8403

XATYWWLL SOP-16 2,500 Units/Tape&Reel

,Power Analog Microelectronics Inc

PAM8403

Filterless 3W Class-D Stereo Audio Amplifier

Outline Dimension

09/2008 Rev 1.3

Dimensions MillimetersSymbol

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

e1.270(TYP)

L 0.400 1.270

θ0º8º

SOP-16