8002

8002 DataSheet V1.0

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CONTENTS
General Description...........................................................................................................................................4Features.............................................................................................................................................................4Applications......................................................................................................................................................4
Typical Application Circuit...............................................................................................................................4Absolute Maximum Ratings..............................................................................................................................5
Electrical Characteristics...................................................................................................................................5Pin Configuration..............................................................................................................................................6Pin Layout.....................................................................................................................................................6Pin Discription...............................................................................................................................................6
Typical Characteristics......................................................................................................................................7
THD, THD+N,S/N........................................................................................................................................7
Power Supply Rejection Ratio (PSRR)...........................................................................................................9Power Dissipation........................................................................................................................................10Output Power...............................................................................................................................................11
Application Information..................................................................................................................................12
BLOCK DIAGRAM...................................................................................................................................12BRIDGE CONFIGURATION EXPLANATION..........................................................................................13
POWER DISSIPATION..............................................................................................................................13POWER SUPPLY BYPASSING...................................................................................................................14
SHUTDOWN FUNCTION.........................................................................................................................14PROPER SELECTION OF EXTERNAL COMPONENTS.........................................................................14
Selection of Input Capacitor Size..................................................................................................................15
AUDIO POWER AMPLIFIER DESIGN......................................................................................................15A 1W/8Ω Audio Amplifier......................................................................................................................15
Physical Size of Chip Package.....................................................................................................................17Page 2 of 17

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FIGURE LISTFigure1. typical Audio Amplifier Application Circuit.........................................................................................4Figure2. SOP Package Pin Distribution...............................................................................................................6Figure3. The block diagram of 8002.................................................................................................................12Figure4. The Package of SOP-8........................................................................................................................17

TABLE LISTS
Table1. Chip Limit Parameter Table....................................................................................................................5Table2. Electrical Characteristics......................................................................................................................5Table3. Pin Discription......................................................................................................................................6Page 3 of 178002
General Description
The 8002 is an audio power amplifier primarily designed for demanding applications in low-power portablesystems. It is capable of delivering 3 watts of continuous average power to an 3Ω BTL load with less than 10%
distortion (THD) from a 5VDC power supply. the 8002 does not require output coupling capacitors or bootstrap
capacitors, and therefore is ideally suited for mobile phone and other low voltage applications where minimal power
consumption is a primary requirement.the 8002 features a low-power consumption shutdown mode.the 8002 containsadvanced pop & click circuitry which eliminates noise which would otherwise occur during turn-on and turn-off
transitions. The 8002 is unity-gain stable and can be configured by external gain-setting resistorsFeatures
Power Output at 5.0V, 10% THD+N, 3Ω 3W (typ)Power Output at 5.0V,10% THD+N,4Ω 2.65W (typ)Power Output at 5.0V,10% THD+N,8Ω 1.8W (typ)
Shutdown Current 0.6µA (typ)Available in space-saving packages: SOP
Improved pop & click circuitry eliminates noise during turn-on and turn-off transitions
2.20- 5.5V operation
No output coupling capacitors, snubber networks or bootstrap capacitors required
Unity-gain stable
External gain configuration capability

Applications
Portable computers
Desktop computers
Low voltage audio systems

Typical Application Circuit

ypical Audio Amplifier Application Circuit
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Absolute Maximum Ratings
Chip Limit Parameter Table

NameParameter

Supply Voltage
Storage Temperature

6.0V−65°C to +150°C

Input Voltage
ESD Susceptibility
Junction Temperature
Thermal ResistanceθJAθJC−0.3V to VDD +0.3V
2000V

150°C
210°C/W
56°C/WWARNING: In addition to limits or any other conditions, the chip may be damaged.

Electrical Characteristics
The following specifications apply for VDD=5V and RL=8Ω, unless otherwise specified. Limits apply for TA = 25°C.
Electrical Characteristics

SymbolIDD

Parameter

Quiescent Power Supply VIN=0V,IO=0A, No load
Current
VIN=0V,IO=0A, 8load

IOFF

Shutdown Current

VOS

Outpt Offset Voltage
Resistor Output
Output Power,3ΩLoad

ROPOTD

THD+N

PSRR

Conditions

8002

Typical
6．5MaxUnits(Limits)

10mA

7．0

10mA

0．825．730

8．5

10uAmVKΩTHD≤1%,f=1KHz

2．3

Output Power,4ΩLoad
Output Power,8ΩLoad

THD≤1%,f=1KHz

2THD≤1%,f=1KHz

1.3

Output Power,3ΩLoad

THD+N≤10%,f=1KHz

3Output Power,4ΩLoad
Output Power,8ΩLoad
Wake-up time
TotalHarmonic
Distortion+Noise

THD+N≤10%,f=1KHz

2．56

THD+N≤10%,f=1KHz

1．8

Power
Ratio

Vripple=200mV sine P-P
Input terminated With 10Ω

SupplyRejection

WWmS

10020Hz ≤ f ≤ 20kHz, AVD = 2

0.2％

RL = 8Ω, PO= 1W

Page 5 of 1763(f=217Hz)67(f=1KHz)

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Pin Configuration
Pin Layout

SOP Package Pin Distribution

Pin Discription

Tabl3. Pin Disnription
Pin NO.

Pin Name

1SD

The device enters in shutdown mode when a high level isapplied on this pin

2

BYP

Bypass capacitor pin which provides the common mode voltage

3+IN

Positive input of the first amplifier, receives the common mode voltage

4-IN

Negative input of the first amplifier, receives the audio input
signal5

Vo1

Negative output

6VDD

Analog VDD input supply.

7GND

Ground connection for circuitry.

8Vo2

Positive output

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Typical Characteristics
THD, THD+N,S/N

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Power Supply Rejection Ratio (PSRR)

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Power Dissipation

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Power Dissipaton

vs Output Power,VDD=2.5V

Output Power

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Application Information
BLOCK DIAGRAM

The block diagram of 8002
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BRIDGE CONFIGURATION EXPLANATIONAs shown in Figure 1, the 8002 has two internal operational amplifiers. The first amplifier’s gain is externallyconfigurable, while the second amplifier is internally fixed in a unity-gain, inverting configuration. The closed-loop
gain of the first amplifier is set by selecting the ratio of Rf to Ri while
the second amplifier’s gain is fixed by the two internal 20kΩ resistors. Figure 1 shows that the output of amplifier one
serves as the input to amplifier two which results in both amplifiers producing signals identical in magnitude, but out ofphase by 180°. Consequently, the differential gain for the IC is

By driving the load differentially through outputs Vo1 and Vo2, an amplifier configuration commonly referred to as“bridged mode” is established. Bridged mode operation is different from the classical single-ended amplifier
configuration where one side of the load is connected to ground.
A bridge amplifier design has a few distinct advantages over the single-ended configuration, as it provides differential
drive to the load, thus doubling output swing for a specified supply voltage. Four times the output power is possible ascompared to a single-ended amplifier under the same conditions. This increase in attainable output power assumes thatthe amplifier is not current limited or clipped. In order to choose an amplifier’s closed-loop gain without causing
excessive clipping, please refer to the Audio Power Amplifier Design section.
A bridge configuration, such as the one used in 8002,also creates a second advantage over single-ended amplifiers.
Since the differential outputs, Vo1 and Vo2, are biased at half-supply, no net DC voltage exists across the load. Thiseliminates the need for an output coupling capacitor which is required in a single supply, single-ended amplifier
configuration. Without an output coupling capacitor, the half-supply bias across the load would result in both increased
internal IC power dissipation and also possible loudspeaker damage.

POWER DISSIPATIONPower dissipation is a major concern when designing a successful amplifier, whether the amplifier is bridged orsingle-ended. A direct consequence of the increased power delivered to the load by a bridge amplifier is an increase ininternal power dissipation. Since the 8002 has two operational amplifiers in one package, the maximum internal power
dissipation is 4 times that of a single-ended amplifier.
The maximum power dissipation for a given application can be derived from the power dissipation graphs or fromEquation 1.

It is critical that the maximum junction temperature TJMAX of 150°C is not exceeded. TJMAX can be determinedfrom the power derating curves by using PDMAX and the PC board foil area. By adding copper foil, the thermal
resistance of the application can be reduced from the free air value of θJA, resulting in higher PDMAX values without
thermal shutdown protection circuitry being activated. Additional copper foil can be added to any of the leads
connected to the 8002. It is especially effective when connected to VDD, GND, and the output pins. Refer to theapplication information on the 8002 reference design board for an example of good heat sinking. If TJMAX still
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additional changes must be made. These changes can include reduced supply voltage, higher load impedance, orreduced ambient temperature. Internal power dissipation is a function of output power. Refer to the TypicalPerformance Characteristics curves for power dissipation information for different output powers and output loading.

POWER SUPPLY BYPASSING
As with any amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection.
The capacitor location on both the bypass and power supply pins should be as close to the device as possible. Typicalapplications employ a 5V regulator with 10µF tantalum or electrolytic capacitor and a ceramic bypass capacitor which
aid in supply stability. This does not eliminate the need for bypassing the supply nodes of the 8002. The selection of abypass capacitor, especially CB, is dependent upon PSRR requirements, click and pop performance (as explained in thesection, Proper Selection of External Components), system cost, and size constraints.

SHUTDOWN FUNCTION
In order to reduce power consumption while not in use, the 8002 contains shutdown circuitry that is used to turn off theamplifier’s bias circuitry. In addition, the 8002 contains a Shutdown Mode pin (LD and MH packages only), allowing
the designer to designate whether the part will be driven into shutdown with a high level logic signal or a low levellogic signal. This allows the designer maximum flexibility in device use, as the Shutdown Mode pin may simply be tied
permanently to either VDD or GND to set the 8002 as either a "shutdown-high" device or a "shutdown-low" device,respectively. The device may then be placed into shutdown mode by toggling the Shutdown pin to the same state as theShutdown Mode pin. For simplicity’s sake, this is called "shutdown same", as the 8002 enters shutdown mode
whenever the two pins are in the same logic state. The MM package lacks this Shutdown Mode feature, and ispermanently fixed as a ‘shutdown-low’ device. The trigger point for either shutdown high or shutdown low is shown asa typical value in the Supply Current vs Shutdown Voltage graphs in the Typical Performance Characteristics section.
It is best to switch between ground and supply for maximum performance. While the device may be disabled withshutdown voltages in between ground and supply, the idle current may be greater than the typical value of 0.1µA. In
either case, the shutdown pin should be tied to a definite voltage to avoid unwanted state changes.
In many applications, a microcontroller or microprocessor output is used to control the shutdown circuitry, which
provides a quick, smooth transition to shutdown. Another solution is to use a single-throw switch in conjunction withan external pull-up resistor (or pull-down, depending on shutdown high or low application). This scheme guarantees
that the shutdown pin will not float, thus preventing unwanted state changes.

PROPER SELECTION OF EXTERNAL COMPONENTS
Proper selection of external components in applications using integrated power amplifiers is critical to optimize device
and system performance. While the 8002 is tolerant of external component combinations, consideration to component
values must be used to maximize overall system quality. The 8002 is unity-gain stable which gives the designer
maximum system flexibility. The 8002 should be used in low gain configurations to minimize THD+N+N values, andmaximize the signal to noise ratio. Low gain configurations require large input signals to obtain a given output power.
Input signals equal to or greater than 1Vrms are available from sources such as audio codecs. Please refer to the section,
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Power Amplifier Design, for a more complete explanation of proper gain selection. Besides gain, one of the major
considerations is the closedloop bandwidth of the amplifier. To a large extent, the bandwidth is dictated by the choice ofexternal components shown in Figure 1. The input coupling capacitor, Ci, forms a first order high pass filter which
limits low frequency response. This value should be chosen based on needed frequency response for a few distinct
reasons.

Selection of Input Capacitor Size
Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized capacitor isneeded to couple in low frequencies without severe attenuation. But in many cases the speakers used in portablesystems, 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 addition to system cost and size, click and pop performance is effected by the size of the input coupling capacitor, Ci.
A larger input coupling capacitor requires more charge to reach its quiescent DC voltage (nominally 1/2 VDD). Thischarge comes from the output via the feedback and is apt to create pops upon device enable. Thus, by minimizing thecapacitor size based on necessary low frequency response, turn-on pops can be minimized.
Besides minimizing the input capacitor size, careful consideration should be paid to the bypass capacitor value. Bypass
capacitor, CB, is the most critical component to minimize turn-on pops since it determines how fast the 8002 turns on.
The slower the 8002’s outputs ramp to their quiescent DC voltage (nominally 1/2 VDD), the smaller the turn-on pop.
Choosing CB equal to 1.0µF along with a small value of Ci (in the range of 0.1µF to 0.39µF), should produce a
virtually clickless and popless shutdown function. While the device will function properly, (no oscillations ormotorboating), with CB equal to 0.1µF, the device will be much more susceptible to turn-on clicks and pops. Thus, avalue of CB equal to 1.0µF is recommended in all but the most cost sensitive designs.

AUDIO POWER AMPLIFIER DESIGNA 1W/8Ω Audio Amplifier
Given:
Power Output
Load Impedance
Input Level
Input Impedance
Bandwidth1Wrms
8Ω
1Vrms
20kΩ
100Hz–20kHz ± 0.25dB

A designer must first determine the minimum supply rail to obtain the specified output power. By extrapolating fromthe Output Power vs Supply Voltage graphs in the Typical Performance Characteristics section, the supply rail can beeasily found.
5V is a standard voltage in most applications, it is chosen for the supply rail. Extra supply voltage creates headroomthat allows the 8002 to reproduce peaks in excess of 1W without producing audible distortion. At this time, the designermust make sure that the power supply choice along with the output impedance does not violate the conditions explainedin the Power Dissipation section.

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Once the power dissipation equations have been addressed, the required differential gain can be determined fromEquation 2.

From Equation 2, the minimum AVD is 2.83; use AVD = 3.Since the desired input impedance was 20kΩ, and with a
AVD impedance of 2, a ratio of 1.5:1 of Rf to Ri results in an allocation of Ri = 20kΩ and Rf = 30kΩ. The final design
step is to address the bandwidth requirements which must be stated as a pair of −3dB frequency points. Five times
away from a −3dB point is 0.17dB down from passband response which is better than the required ±0.25dB specified.

As stated in the External Components section, Ri in conjunction with Ci create a highpass filter.

Use 0.39uf.The high frequency pole is determined by the product of the desired frequency pole, fH, and the differential
gain, AVD. With a AVD = 3 and fH = 100kHz, the resulting GBWP = 300kHz which is much smaller than the 8002
GBWP of 2.5MHz. This figure displays that if a designer has a need to design an amplifier with a higher differential
gain, the 8002 can still be used without running into bandwidth limitations.

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Physical Size of Chip Package

SymbolA
A1A2bc
DEE1e
Lθ

Dimensions In Millimeters
MinMax
1.350
1.750
0.100
0.250
1.350
1.55
0.330
0.510
0.170
0.250
4.700
5.100
3.800
4.000
5.800
6.200
1.270(BSC)
0.400
1.270
0°
8°

Dimensions In Inches
Min
0.053
0.004
0.053
0.013
0.006
0.185
0.150
0.228
0.050(BSC)
0.016
0°

The Package of SOP-8

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Max
0.069
0.010
0.061
0.020
0.010
0.200
0.157
0.244
0.050
8°