TEXAS INSTRUMENTS TPA721 Technical data

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1
2
3
4

8
7
6
5

SHUTDOWN

BYPASS

IN+
IN–

VO–
GND
V

DD

VO+

D OR DGN PACKAGE

(TOP VIEW)

Audio

Input

Bias

Control

V

DD

700 mW

6

5

7

VO+

V

DD

1

24BYPASS

IN–

VDD/2

C

I

R

I

C

S

C

B

R

F

SHUTDOWN

VO– 8

GND

From System Control

3 IN+

–

+

–

+

700-mW MONO LOW-VOLTAGE AUDIO POWER AMPLIFIER

FEATURES DESCRIPTION

• Fully Specified for 3.3-V and 5-V Operation

• Wide Power Supply Compatibility 2.5 V – 5.5 V

• Output Power for R

– 700 mW at V
– 250 mW at V

DD
DD

• Integrated Depop Circuitry

• Thermal and Short-Circuit Protection

• Surface-Mount Packaging

– SOIC
– PowerPAD™ MSOP

= 8 Ω

L

= 5 V, BTL
= 3.3 V, BTL load at less than 0.6% THD+N throughout voice band

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

The TPA721 is a bridge-tied load (BTL) audio power
amplifier developed especially for low-voltage appli­cations where internal speakers are required.
Operating with a 3.3-V supply, the TPA721 can
deliver 250-mW of continuous power into a BTL 8-Ω

frequencies. Although this device is characterized out
to 20 kHz, its operation is optimized for narrower
band applications such as wireless communications.
The BTL configuration eliminates the need for exter­nal coupling capacitors on the output in most appli­cations, which is particularly important for small
battery-powered equipment. This device features a
shutdown mode for power-sensitive applications with
a supply current of 7 µA during shutdown. The
TPA721 is available in an 8-pin SOIC surface-mount
package and the surface-mount PowerPAD MSOP,
which reduces board space by 50% and height by
40%.

PowerPAD is a trademark of Texas Instruments.

PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Copyright © 1998–2004, Texas Instruments Incorporated

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TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated
circuits be handled with appropriate precautions. Failure to observe proper handling and installation
procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.

AVAILABLE OPTIONS

PACKAGED DEVICES

T

A

–40°C to 85°C TPA721D TPA721DGN ABC

(1) In the D package, the maximum output power is thermally limited to 350 mW; 700 mW peaks can be

driven, as long as the RMS value is less than 350 mW.

(2) The D and DGN packages are available taped and reeled. To order a taped and reeled part, add the

suffix R to the part number (e.g., TPA301DR).

SMALL OUTLINE

(D) (DGN)

(1)

Terminal Functions

TERMINAL

NAME NO.

BYPASS 2 I
GND 7 GND is the ground connection.

IN- 4 I IN- is the inverting input. IN- is typically used as the audio input terminal.
IN+ 3 I IN+ is the noninverting input. IN+ is typically tied to the BYPASS terminal.
SHUTDOWN 1 I SHUTDOWN places the entire device in shutdown mode when held high.
V

DD

VO+ 5 O VO+ is the positive BTL output.
VO– 8 O VO- is the negative BTL output.

I/O DESCRIPTION

BYPASS is the tap to the voltage divider for internal mid-supply bias. This terminal should be connected to a

0.1-µF to 2.2-µF capacitor when used as an audio amplifier.

6 V

is the supply voltage terminal.

DD

(2)

MSOP

MSOP

SYMBOLIZATION

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)

V

Supply voltage 6 V

DD

V

Input voltage –0.3 V to V

I

Continuous total power dissipation Internally limited (see Dissipation Rating Table)

T

Operating free-air temperature range –40°C to 85°C

A

T

Operating junction temperature range –40°C to 150°C

J

T

Storage temperature range –65°C to 150°C

stg

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds 260°C

(1) Stresses beyond those listed under "absolute maximum ratings” may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

2

(1)

UNIT

+0.3 V

DD

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DISSIPATION RATING TABLE

PACKAGE TA≤ 25°C DERATING FACTOR TA= 70°C TA= 85°C

D 725 mW 5.8 mW/°C 464 mW 377 mW

DGN 2.14 W

(1)

17.1 mW/°C 1.37 W 1.11 W

(1) See the Texas Instruments document, PowerPAD Thermally Enhanced Package Application Report

(SLMA002), for more information on the PowerPAD package. The thermal data was measured on a
PCB layout based on the information in the section entitled Texas Instruments Recommended Board
for PowerPAD on page 33 of that document.

RECOMMENDED OPERATING CONDITIONS

V
V
V
T

Supply voltage 2.5 5.5 V

DD

High-level voltage, (SHUTDOWN) 0.9 V

IH

Low-level voltage, (SHUTDOWN) 0.1 V

IL

Operating free-air temperature –40 85 °C

A

ELECTRICAL CHARACTERISTICS

at specified free-air temperature, V

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V

OO

PSRR Power supply rejection ratio V
I

DD

I

DD(SD)

|IIH| SHUTDOWN, V
|IIL| SHUTDOWN, V

Output offset voltage (measured differentially) SHUTDOWN = 0 V, RL= 8 Ω, RF = 10 kΩ 20 mV

Supply current SHUTDOWN = 0 V, RF = 10 kΩ 1.25 2.5 mA
Supply current, shutdown mode (see Figure 4 ) SHUTDOWN = VDD, RF = 10 kΩ 7 50 µA

= 3.3 V, TA= 25°C (unless otherwise noted)

DD

= 3.2 V to 3.4 V 85 dB

DD

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

MIN MAX UNIT

DD

= 3.3 V, Vi= 3.3 V 1 µA

DD

= 3.3 V, Vi= 0 V 1 µA

DD

TPA721

V
V

DD

OPERATING CHARACTERISTICS

V

= 3.3 V, TA= 25°C, RL= 8 Ω

DD

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

P

O

Output power

(1)

THD = 0.5%, See Figure 9 250 mW
THD + N Total harmonic distortion plus noise PO= 250 mW, f = 200 Hz to 4 kHz, See Figure 7 0.55%
B

OM

B

1

k

SVR

V

n

Maximum output power bandwidth Gain = 2, THD = 2%, See Figure 7 20 kHz
Unity-gain bandwidth Open loop, See Figure 15 1.4 MHz
Supply ripple rejection ratio f = 1 kHz, CB= 1 µF, See Figure 2 79 dB
Noise output voltage Gain = 1, CB= 0.1 µF, See Figure 19 17 µV(rms)

(1) Output power is measured at the output terminals of the device at f = 1 kHz.

ELECTRICAL CHARACTERISTICS

at specified free-air temperature, V

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

V
PSRR Power supply rejection ratio V
I

DD

I

DD(SD)

|IIH| SHUTDOWN, V
|IIL| SHUTDOWN, V

Output offset voltage (measured differentially) SHUTDOWN = 0 V, RL= 8 Ω, RF = 10 kΩ 20 mV

OO

Supply current SHUTDOWN = 0 V, RF = 10 kΩ 1.25 2.5 mA
Supply current, shutdown mode (see Figure 4 ) SHUTDOWN = VDD, RF = 10 kΩ 50 100 µA

= 5 V, TA= 25°C (unless otherwise noted)

DD

= 4.9 V to 5.1 V 78 dB

DD

= 5.5 V, Vi= V

DD

= 5.5 V, Vi= 0 V 1 µA

DD

DD

1 µA

3

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Audio

Input

Bias

Control

V

DD

6

5

7

VO+

V

DD

1

24BYPASS

IN–

VDD/2

C

I

R

I

C

S

C

B

R

F

SHUTDOWN

VO– 8

R

L = 8

Ω

GND

3 IN+

–

+

–

+

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

OPERATING CHARACTERISTICS

V

= 5 V, TA= 25°C, RL= 8 Ω

DD

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

P

O

Output power THD = 0.5%, See Figure 13 700
THD + N Total harmonic distortion plus noise PO= 250 mW, f = 200 Hz to 4 kHz, See Figure 11 0.5%
B

OM

B

1

k

SVR

V

n

Maximum output power bandwidth Gain = 2, THD = 2%, See Figure 11 20 kHz

Unity-gain bandwidth Open loop, See Figure 16 1.4 MHz

Supply ripple rejection ratio f = 1 kHz, CB= 1 µF, See Figure 2 80 dB

Noise output voltage Gain = 1, CB= 0.1 µF, See Figure 20 17 µV(rms)

(1) The DGN package, properly mounted, can conduct 700-mW RMS power continuously. The D package can only conduct 350-mW RMS

power continuously with peaks to 700 mW.

PARAMETER MEASUREMENT INFORMATION

(1)

mW

Figure 1. BTL Mode Test Circuit

4

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−50

−60

−80

−100
20 100 1k

−30

−20

f − Frequency − Hz

0

10k 20k

−10

−40

−70

−90

VDD = 5 V

VDD = 3.3 V

RL = 8 Ω
CB = 1 µF
BTL

k

SVR

−Supply Ripple Rejection Ratio − dB

VDD − Supply Voltage − V

1.8

0.8

0.6

1

3 4

5.5

5

I

DD

− Supply Current − mA

2.5 3.5 4.5

1.6

1.2

1.4

SHUTDOWN = 0 V
RF = 10 kΩ

k

SVR

I

DD

P

O

Supply ripple rejection ratio vs Frequency 2
Supply current vs Supply voltage 3, 4

Output power

THD+N Total harmonic distortion plus noise

Open-loop gain and phase vs Frequency 15, 16
Closed-loop gain and phase vs Frequency 17, 18

V

n

P

D

Output noise voltage vs Frequency 19, 20
Power dissipation vs Output power 21, 22

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

TYPICAL CHARACTERISTICS

Table of Graphs

FIGURE

vs Supply voltage 5
vs Load resistance 6
vs Frequency 7, 8, 11, 12
vs Output power 9, 10, 13, 14

SUPPLY RIPPLE REJECTION RATIO SUPPLY CURRENT

vs vs

FREQUENCY SUPPLY VOLTAGE

Figure 2. Figure 3.

5

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VDD − Supply Voltage − V

20
10

0

3 43.5 4.5

60

5

30

SHUTDOWN = V

DD

RF = 10 kΩ

40

50

5.52.5

I

DD

− Supply Current − Aµ

70

80

90

VDD − Supply Voltage − V

600

400

200

0

2.5 3.53 4 5.5

1000

P

4.5 5

O

− Output Power − mW

800

THD+N 1%
f = 1 kHz
BTL

RL = 32 Ω

RL = 8 Ω

RL − Load Resistance − Ω

300

200

100

0

16 3224 40 64

800

8

P

48 56

O

− Output Power − mW

400

THD+N = 1%
f = 1 kHz
BTL

VDD = 5 V

500

600

VDD = 3.3 V

700

f − Frequency − Hz

THD+N −Total Harmonic Distortion + Noise − %

AV = −2 V/V

VDD = 3.3 V
PO = 250 mW
RL = 8 Ω
BTL

20 1k 10k

1

0.01

10

0.1

20k100

AV = −20 V/V

AV = −10 V/V

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

TYPICAL CHARACTERISTICS (continued)

SUPPLY CURRENT OUTPUT POWER

vs vs

SUPPLY VOLTAGE SUPPLY VOLTAGE

Figure 4. Figure 5.

OUTPUT POWER TOTAL HARMONIC DISTORTION + NOISE

vs vs

LOAD RESISTANCE FREQUENCY

6

Figure 6. Figure 7.

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f − Frequency − Hz

THD+N −Total Harmonic Distortion + Noise − %

PO = 125 mW

VDD = 3.3 V
RL = 8 Ω
AV = −2 V/V
BTL

20 1k 10k

1

0.01

10

0.1

20k100

PO = 50 mW

PO = 250 mW

PO − Output Power − W

THD+N −Total Harmonic Distortion + Noise − %

0 0.15 0.4

1

0.01

10

0.1

0.2 0.25 0.3 0.35

VDD = 3.3 V
f = 1 kHz
AV = −2 V/V
BTL

0.05 0.1

RL = 8 Ω

PO − Output Power − W

THD+N −Total Harmonic Distortion + Noise − %

f = 20 kHz

VDD = 3.3 V
RL = 8 Ω
CB = 1 µF
AV = −2 V/V
BTL

0.01 0.1 1

1

0.01

10

0.1

f = 1 kHz

f = 10 kHz

f = 20 Hz

f − Frequency − Hz

THD+N −Total Harmonic Distortion + Noise − %

AV =− 2 V/V

VDD = 5 V
PO = 700 mW
RL = 8 Ω
BTL

20 1k 10k

1

0.01

10

0.1

20k100

AV = −20 V/V

AV = −10 V/V

TYPICAL CHARACTERISTICS (continued)

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

TOTAL HARMONIC DISTORTION + NOISE TOTAL HARMONIC DISTORTION + NOISE

TOTAL HARMONIC DISTORTION + NOISE TOTAL HARMONIC DISTORTION + NOISE

vs vs

FREQUENCY OUTPUT POWER

Figure 8. Figure 9.

vs vs

OUTPUT POWER FREQUENCY

Figure 10. Figure 11.

7

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f − Frequency − Hz

THD+N −Total Harmonic Distortion + Noise − %

PO = 700 mW

VDD = 5 V
RL = 8 Ω
AV = −2 V/V
BTL

20 1k 10k

1

0.01

10

0.1

20k100

PO = 50 mW

PO = 350 mW

PO − Output Power − W

0.1 0.2 10.4 0.5 0.7 0.8

THD+N −Total Harmonic Distortion + Noise − %

RL = 8 Ω

VDD = 5 V
f = 1 kHz
AV = −2 V/V
BTL

1

0.01

10

0.1

0.3 0.6 0.9

PO − Output Power − W

THD+N −Total Harmonic Distortion + Noise − %

f = 20 Hz

VDD = 5 V
RL = 8 Ω
CB = 1 µF
AV = −2 V/V
BTL

0.01 0.1 1

1

0.01

10

0.1

f = 1 kHz

f = 10 kHz

f = 20 kHz

TPA721

SLOS231E – NOVEMBER 1998 – REVISED JUNE 2004

TYPICAL CHARACTERISTICS (continued)

TOTAL HARMONIC DISTORTION + NOISE TOTAL HARMONIC DISTORTION + NOISE

vs vs

FREQUENCY OUTPUT POWER

Figure 12. Figure 13.

TOTAL HARMONIC DISTORTION + NOISE

vs

OUTPUT POWER

8

Figure 14.