Datasheet

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LM4871

www.ti.com

SNAS002F –FEBRUARY 2000–REVISED MAY 2013

LM4871 3W Audio Power Amplifier with Shutdown Mode

Check for Samples: LM4871

FEATURES

DESCRIPTION

The LM4871 is a mono bridged audio power amplifier

• No Output Coupling Capacitors, Bootstrap

capable of delivering 3W of continuous average

Capacitors, or Snubber Circuits Required

power into a 3Ω load with less than 10% THD when

• Unity-gain Stable

• WSON, VSSOP, SOIC, or PDIP Packaging

conserve power in portable applications, the

LM4871's micropower shutdown mode (I

= 0.6µA,

• External Gain Configuration Capability

typ) is activated when V

is applied to the

• Pin Compatible with the LM4861

SHUTDOWN pin.

Boomer audio power amplifiers are designed

APPLICATIONS

specifically to provide high power, high fidelity audio

• Portable Computers

output. They require few external components and

• Desktop Computers operate on low supply voltages from 2.0V to 5.5V.

Since the LM4871 does not require output coupling

• Low Voltage Audio Systems

capacitors, bootstrap capacitors, or snubber

networks, it is ideally suited for low-power portable

KEY SPECIFICATIONS

systems that require minimum volume and weight.

• PO at 10% THD+N, 1kHz

Additional LM4871 features include thermal shutdown

– LM4871LD: 3Ω , 4Ω Loads; 3W (typ),

protection, unity-gain stability, and external gain set.

2.5 W (typ)

Note: An LM4871LD that has been properly mounted

– All other LM4871 Packages: 8Ω load

to a circuit board will deliver 3W into 3Ω (at 10%

1.5 W (typ)

THD). The other package options for the LM4871 will

• Shutdown Current 0.6µA (typ)

deliver 1.5W into 8Ω (at 10% THD). See the

Application Information section for further information

• Supply Voltage Range 2.0V to 5.5 V

concerning the LM4871LD, LM4871MM, LM4871M,

• THD at 1kHz at 1W Continuous Average

and the LM4871N.

Output Power into 8Ω 0.5% (max)

Connection Diagrams

Figure 1. VSSOP, Small Outline, and PDIP Figure 2. WSON Package (Top View)

Package

See Package Number NGN0008A

Top View

See Package Number DGK0008A, D0008A, or

D0008E

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.

2All trademarks are the property of their respective owners.

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.

Summary of content (23 pages)

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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 LM4871 3W Audio Power Amplifier with Shutdown Mode Check for Samples: LM4871 FEATURES DESCRIPTION • The LM4871 is a mono bridged audio power amplifier capable of delivering 3W of continuous average power into a 3Ω load with less than 10% THD when powered by a 5V power supply (see Note). To conserve power in portable applications, the LM4871's micropower shutdown mode (IQ = 0.6µA, typ) is activated when VDD is applied to the SHUTDOWN pin.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com Typical Application Figure 3. Typical Audio Amplifier Application Circuit These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 Absolute Maximum Ratings (1) (2) Supply Voltage 6.0V −65°C to +150°C Supply Temperature −0.3V to VDD to +0.3V Input Voltage Power Dissipation (3) Internally Limited (4) 5000V ESD Susceptibility ESD Susceptibility (5) 250V Junction Temperature 150°C Soldering Information Small Outline Package Vapor Phase (60 sec.) 215°C Infrared (15 sec.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com Electrical Characteristics(1)(2) (continued) The following specifications apply for VDD = 5V and RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C. LM4871 Symbol Po Output Power THD+N PSRR (5) Parameter Conditions Min (3) Typical (4) Limit (3) Units (Limits) THD = 1%, f = 1kHz LM4871LD, RL = 3Ω (5) LM4871LD, RL = 4Ω (5) LM4871, RL = 8Ω (5) 2.38 2 1.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 Typical Performance Characteristics NGN Specific Characteristics LM4871LD THD+N vs Output Power LM4871LD THD+N vs Frequency Figure 4. Figure 5. LM4871LD THD+N vs Frequency LM4871LD THD+N vs Output Power Figure 6. Figure 7. LM4871LD Power Dissipation vs Output Power LM4871LD Power Derating Curve Figure 8.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics Non-NGN Specific Characteristics 6 THD+N vs Frequency THD+N vs Frequency Figure 10. Figure 11. THD+N vs Frequency THD+N vs Output Power Figure 12. Figure 13. THD+N vs Output Power THD+N vs Output Power Figure 14. Figure 15.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 Typical Performance Characteristics Non-NGN Specific Characteristics (continued) Output Power vs Supply Voltage Output Power vs Supply Voltage Figure 16. Figure 17. Output Power vs Supply Voltage Output Power vs Load Resistance Figure 18. Figure 19. Power Dissipation vs Output Power Figure 20. Power Derating Curve Figure 21.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics Non-NGN Specific Characteristics (continued) Clipping Voltage vs Supply Voltage 8 Noise Floor Figure 22. Figure 23. Frequency Response vs Input Capacitor Size Power Supply Rejection Ratio Figure 24. Figure 25. Open Loop Frequency Response Supply Current vs Supply Voltage Figure 26. Figure 27.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 APPLICATION INFORMATION EXPOSED-DAP PACKAGE PCB MOUNTING CONSIDERATION The LM4871's exposed-DAP (die attach paddle) package (NGN) provides a low thermal resistance between the die and the PCB to which the part is mounted and soldered. This allows rapid heat transfer from the die to the surrounding PCB copper traces, ground plane, and surrounding air. The result is a low voltage audio power amplifier that produces 2W at ≤ 1% THD with a 4Ω load.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com 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 as compared to a single-ended amplifier under the same conditions. This increase in attainable output power assumes that the amplifier is not current limited or clipped.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 SHUTDOWN FUNCTION In order to reduce power consumption while not in use, the LM4871 contains a shutdown pin to externally turn off the amplifier's bias circuitry. This shutdown feature turns the amplifier off when a logic high is placed on the shutdown pin. The trigger point between a logic low and logic high level is typically half- supply. It is best to switch between ground and supply to provide maximum device performance.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com AUDIO POWER AMPLIFIER DESIGN Design a 1W/8Ω Audio Amplifier Given: Power Output 1 Wrms Load Impedance 8Ω Input Level 1 Vrms Input Impedance 20 kΩ Bandwidth 100 Hz–20 kHz ± 0.25 dB A designer must first determine the minimum supply rail to obtain the specified output power. By extrapolating from the Output Power vs Supply Voltage graphs in the Typical Performance Characteristics section, the supply rail can be easily found.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 Demonstration Board Layout Figure 28. Recommended NGN PC Board Layout: Component-Side Silkscreen Figure 29. Recommended NGN PC Board Layout: Component-Side Layout Figure 30. Recommended NGN PC Board Layout: Bottom-Side Layout LM4871 MDA MWA 3W Audio Power Amplifier With Shutdown Mode Figure 31.
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LM4871 SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 www.ti.com Die/Wafer Characteristics Fabrication Attributes General Die Information Physical Die Identification LM4871C Bond Pad Opening Size (min) 102µm x 102µm Die Step C Bond Pad Metalization 0.5% COPPER_BAL.
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LM4871 www.ti.com SNAS002F – FEBRUARY 2000 – REVISED MAY 2013 REVISION HISTORY Changes from Revision E (May 2013) to Revision F • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 26-Aug-2013 (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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PACKAGE MATERIALS INFORMATION www.ti.com 12-Aug-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM4871LD Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant WSON NGN 8 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM4871LD/NOPB WSON NGN 8 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM4871MM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 12-Aug-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4871LD WSON NGN 8 1000 210.0 185.0 35.0 LM4871LD/NOPB WSON NGN 8 1000 213.0 191.0 55.0 LM4871MM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM4871MMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.0 LM4871MX SOIC D 8 2500 367.0 367.0 35.0 LM4871MX/NOPB SOIC D 8 2500 367.0 367.0 35.
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MECHANICAL DATA NGN0008A LDC08A (Rev B) www.ti.
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