Datasheet

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LM4991

www.ti.com

SNAS217A –MAY 2004–REVISED APRIL 2013

LM4991 3W Audio Power Amplifier with Shutdown Mode

Check for Samples: LM4991

FEATURES

DESCRIPTION

The LM4991 is a mono bridged audio power amplifier

• Available in Space-Saving WSON and SOIC

capable of delivering 3W of continuous average

Packages

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

• Ultra Low Current Shutdown Mode

• Can Drive Capacitive Loads up to 500pF

conserve power in portable applications, the

LM4991's micropower shutdown mode (I

= 0.1µA,

• Improved Click and Pop Circuitry Reduces

typ) is activated when V

is applied to the

Noises During Turn-On and Turn-Off

SHUTDOWN pin.

Transitions

Boomer audio power amplifiers are designed

• 2.2 - 5.5V Operation

specifically to provide high power, high fidelity audio

• No Output Coupling Capacitors, Snubber

output. They require few external components and

Networks, Bootstrap Capacitors or Gain-

operate on low supply voltages from 2.2V to 5.5V.

Setting Resistors Required

Since the LM4991 does not require output coupling

capacitors, bootstrap capacitors, or snubber

• Unity-Gain Stable

networks, it is ideally suited for low-power portable

systems that require minimum volume and weight.

APPLICATIONS

Additional LM4991 features include thermal shutdown

• Wireless and Cellular Handsets

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

• PDAs

Note: An LM4991LD that has been properly mounted

• Portable Computers

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

• Desktop Computers

THD). The other package options for the LM4991 will

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

KEY SPECIFICATIONS

Application Information sections for further

information concerning the LM4991LD and

• Improved PSRR at 217kHz and 1kHz: 64 dB

LM4991M.

(typ)

• P

at V

= 5.0V, 10% THD, 1kHz

– LM4991LD (only), 3Ω, 4Ω: 3W (typ), 2.5 W

(typ)

– All packages, 8Ω load: 1.5 W (typ)

• Shutdown current: 0.1µA (typ)

Connection Diagrams

Top View Top View

Figure 1. SOIC Package Figure 2. WSON Package

See Package Number D0008A See Package Number NGN0008A

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 (22 pages)

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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 LM4991 3W Audio Power Amplifier with Shutdown Mode Check for Samples: LM4991 FEATURES DESCRIPTION • The LM4991 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 below). To conserve power in portable applications, the LM4991's micropower shutdown mode (ISD = 0.
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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 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. Absolute Maximum Ratings (1) (2) Supply Voltage 6.0V −65°C to +150°C Supply Temperature −0.3V to VDD to +0.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 Electrical Characteristics VDD = 5V (1) (2) The following specifications apply for VDD = 5V and RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C. LM4991 Parameter IDD Test Conditions Typ (3) Quiescent Power Supply Current VIN = 0V, no Load 3 7 VIN = 0V, RL = 8Ω 4 10 VSHUTDOWN = VDD 0.1 2.
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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 2013 www.ti.com Electrical Characteristics VDD = 3V (1) (2) (continued) The following specifications apply for VDD = 3V and RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C. LM4991 Parameter PSRR Test Conditions Typ (3) Power Supply Rejection Ratio VRIPPLE = 200mV sine p-p, Input terminated with 10Ω, f = 1kHz Electrical Characteristics VDD = 2.6V Units (Limits) Limit (4) 68 dB (1) (2) The following specifications apply for VDD = 2.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 Typical Performance Characteristics LD and MA Specific Characteristics THD+N vs Frequency VDD = 5V, RL = 4Ω, and PO = 1W THD+N vs Output Power VDD = 5V, RL = 4Ω, and f = 1 kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.01 20 0.1 100 1k 10k 20k 0.01 10m 100m FREQUENCY (Hz) OUTPUT POWER (W) Figure 4. Figure 5.
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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics THD+N vs Frequency VDD = 5V, RL = 8Ω, and PO = 500mW THD+N vs Frequency VDD = 3V, RL = 4Ω, and PO = 500mW 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 20 100 1k 0.01 20 10k 20k 1k 10k 20k FREQUENCY (Hz) Figure 6. Figure 7. THD+N vs Frequency VDD = 3V, RL = 8Ω, and PO = 250mW THD+N vs Frequency VDD = 2.6V, RL = 4Ω, and PO = 150mW 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 3V, RL = 4Ω, and f = 1kHz THD+N vs Output Power VDD = 3V, RL = 8Ω, and f = 1kHz 1 1 THD+N (%) 10 THD+N (%) 10 0.1 0.1 0.01 10m 100m 0.01 10m 1 100m 1 OUTPUT POWER (W) OUTPUT POWER (W) Figure 12. Figure 13. THD+N vs Output Power VDD = 2.6V, RL = 4Ω, and f = 1kHz THD+N vs Output Power VDD = 2.
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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 3V, RL = 8Ω, input floating 0 0 -10 -10 -20 -20 -30 -30 PSRR LEVEL (dB) PSRR LEVEL (dB) Power Supply Rejection Ratio (PSRR) vs Frequency VDD = 3V, RL = 8Ω, input 10Ω terminated -40 -50 -60 -70 -40 -50 -60 -70 -80 -80 -90 -90 -100 20 100 1k -100 20 10k 20k 100 FREQUENCY (Hz) 10k 20k FREQUENCY (Hz) Figure 19.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 Typical Performance Characteristics (continued) Power Dissipation vs Output Power, VDD = 5V Power Dissipation vs Output Power, VDD = 3V 0.5 1.4 0.45 : POWER DISSIPATION (W) POWER DISSIPATION (W) 1.2 : 1 0.8 0.6 : 0.4 0.2 0.4 0.35 : 0.3 0.25 0.2 0.15 0.1 0.05 0 0 0 0.5 1 1.5 2 2.5 OUTPUT POWER (W) 0 0.2 0.4 0.6 0.8 1 OUTPUT POWER (W) Figure 24. Figure 25. Power Dissipation vs Output Power, VDD = 2.
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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Output Power vs Supply Voltage, RL = 4Ω Output Power vs Supply Voltage, RL = 8Ω 3 3.5 f = 1kHz f = 1kHz 2.5 OUTPUT POWER (W) OUTPUT POWER (W) 3 2.5 10% THD+N 2 1.5 1% THD+N 1 2 10% THD+N 1.5 1 1% THD+N 500m 500m 0 2.2 3 4 5 0 2.2 5.5 3 5 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure 30. Figure 31.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 APPLICATION INFORMATION EXPOSED-DAP PACKAGE PCB MOUNTING CONSIDERATION The LM4991's exposed-DAP (die attach paddle) package (LD) 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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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 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.
PAGE 13
LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 SHUTDOWN FUNCTION In order to reduce power consumption while not in use, the LM4991 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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LM4991 SNAS217A – MAY 2004 – REVISED APRIL 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 theTypical Performance Characteristics section, the supply rail can be easily found.
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LM4991 www.ti.com SNAS217A – MAY 2004 – REVISED APRIL 2013 REVISION HISTORY Changes from Original (April 2013) to Revision A • 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 18-Oct-2013 Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device 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 LM4991LD/NOPB WSON NGN 8 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM4991LDX/NOPB WSON NGN 8 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM4991MAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-Apr-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4991LD/NOPB WSON NGN 8 1000 213.0 191.0 55.0 LM4991LDX/NOPB WSON NGN 8 4500 367.0 367.0 35.0 LM4991MAX/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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