Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Audio amplifier 1-channel (mono) Class AB WSON 8 (3x2.5)

LM4941, LM4941SDBD, LM4941TMBD

www.ti.com

SNAS347C –JUNE 2006–REVISED MAY 2013

LM4941 1.25 Watt Fully Differential Audio Power Amplifier

With RF Suppression and Shutdown

Check for Samples: LM4941, LM4941SDBD, LM4941TMBD

FEATURES

DESCRIPTION

The LM4941 is a fully differential audio power

• Improved RF Suppression, By Up to 20dB

amplifier primarily designed for demanding

Over Previous Designs in Selected

applications in mobile phones and other portable

Applications

communication device applications. It is capable of

• Fully Differential Amplification

delivering 1.25 watts of continuous average power to

a 8Ω load with less than 1% distortion (THD+N) from

• Available in Space-Saving DSBGA Package

a 5V

power supply. The LM4941 does not require

• Ultra Low Current Shutdown Mode

output coupling capacitors or bootstrap capacitors,

• Can Drive Capacitive Loads up to 100pF

and therefore is ideally suited for mobile phone and

• Improved Pop & Click Circuitry Eliminates

other small form factor applications where minimal

PCB space is a primary requirement.

Noises During Turn-On and Turn-Off

Transitions

The LM4941 also features proprietary internal

• 2.4 - 5.5V Operation

circuitry that suppresses the coupling of RF signals

into the chip. This is important because certain types

• No Output Coupling Capacitors, Snubber

of RF signals (such as GSM) can couple into audio

Networks or Bootstrap Capacitors Required

amplifiers in such a way that part of the signal is

heard through the speaker. The RF suppression

APPLICATIONS

circuitry in the LM4941 makes it well-suited for

• Mobile Phones

portable applications in which strong RF signals

generated by an antenna from or a cellular phone or

• PDAs

other portable electronic device may couple audibly

• Portable Electronic Devices

into the amplifier.

Other features include a low-power consumption

KEY SPECIFICATIONS

shutdown mode, internal thermal shutdown

• Improved PSRR at 217Hz 95dB (typ)

protection, and advanced pop & click circuitry.

• Power Output, V

= 5.0V, R

= 8Ω, 1% THD+N

1.25W (typ)

• Power Output, V

= 3.0V, R

= 8Ω, 1% THD+N

430mW (typ)

• Shutdown Current 0.1µA (typ)

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 (21 pages)

PAGE 1
LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 LM4941 1.25 Watt Fully Differential Audio Power Amplifier With RF Suppression and Shutdown Check for Samples: LM4941, LM4941SDBD, LM4941TMBD FEATURES DESCRIPTION • The LM4941 is a fully differential audio power amplifier primarily designed for demanding applications in mobile phones and other portable communication device applications. It is capable of delivering 1.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Typical Application VDD CS 1 PF RF1 + 20 k: Ri1 20 k: -IN - Differential Input + Bias SHUTDOWN 1.0 PF + Differential Input CB RL Common Mode 8: - BYP VO- + +IN Ri2 VO+ 20 k: GND RF2 20 k: Figure 1.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 Absolute Maximum Ratings (1) (2) (3) Supply Voltage 6.0V −65°C to +150°C Storage Temperature −0.3V to VDD +0.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Electrical Characteristics VDD = 5V(1)(2) (continued) The following specifications apply for VDD = 5V, AV = 1V/V, and 8Ω load unless otherwise specified. Limits apply for TA = 25°C.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 External Components Description (Figure 1) Components Functional Description 1. CS Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing section for information concerning proper placement and selection of the supply bypass capacitor. 2. CB Bypass pin capacitor which provides half-supply filtering.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics Data taken with Bandwidth = 80kHz, AV = 1V/V and inputs are AC-coupled except where specified. THD+N vs Output Power VDD = 5V, RL = 8Ω, f = 1kHz 10 10 1 THD+N (%) THD+N (%) 1 0.1 0.01 0.1 0.01 0.001 10m 100m 1 0.001 10m 2 OUTPUT POWER (W) 10 100m Figure 4. Figure 5.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 Typical Performance Characteristics (continued) Data taken with Bandwidth = 80kHz, AV = 1V/V and inputs are AC-coupled except where specified. CMRR vs Frequency VDD = 5V, RL = 8Ω -40 -50 -50 -60 -60 CMRR (dB) CMRR (dB) -40 -70 -70 -80 -80 -90 -90 -100 20 100 CMRR vs Frequency VDD = 3V, RL = 8Ω -100 20 10k 20k 1k 100 FREQUENCY (Hz) Figure 10. Figure 11.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Data taken with Bandwidth = 80kHz, AV = 1V/V and inputs are AC-coupled except where specified. Output Power vs Supply Voltage RL = 8Ω, Top-THD+N = 10%; Bot-THD+N = 1% Clipping Voltage vs Supply Voltage 0.5 2 1.8 0.4 DROPOUT VOLTAGE (V) OUTPUT POWER (W) 1.6 1.4 1.2 1 0.8 0.6 0.3 0.2 0.1 0.4 0.2 0 0 2 2 2.5 3 3.5 4 4.5 5 5.5 2.5 3 6 3.5 4 4.5 5 5.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 APPLICATION INFORMATION OPTIMIZING RF IMMUNITY The internal circuitry of the LM4941 suppresses the amount of RF signal that is coupled into the chip. However, certain external factors, such as output trace length, output trace orientation, distance between the chip and the antenna, antenna strength, speaker type, and type of RF signal, may affect the RF immunity of the LM4941.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Since the LM4941 has bridged outputs, the maximum internal power dissipation is four times that of a singleended amplifier. Even with this substantial increase in power dissipation, the LM4941 does not require additional heatsinking under most operating conditions and output loading. From Equation 3, assuming a 5V power supply and an 8Ω load, the maximum power dissipation point is 625mW.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 When using DC coupled inputs, special care must be taken to match the values of the input resistors (Ri1 and Ri2) to each other. Because of the balanced nature of differential amplifiers, resistor matching differences can result in net DC currents across the load. This DC current can increase power consumption, internal IC power dissipation, reduce PSRR, and possibly damaging the loudspeaker.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com Figure 23. Recommended TM Board Layout: Bottom Layer Recommended WSON Board Layout Figure 24. Recommended WSON Board Layout: Top Layer 12 Submit Documentation Feedback Figure 25.
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LM4941, LM4941SDBD, LM4941TMBD www.ti.com SNAS347C – JUNE 2006 – REVISED MAY 2013 Figure 26. Recommended WSON Board Layout: Bottom Layer LM4941 Reference Design Boards Bill Of Materials Designator Value Tolerance Part Description Ri1, Ri2 20kΩ 0.10% 1/10W, 0.1% 0805 Resistor Rf1, Rf2 20kΩ 0.10% 1/10W, 0.1% 0805 Resistor Ci1, Ci2 0Ω Cb, Cs 1μF Comments 1/10W, 0.1% 0805 Resistor 10% In, Out, VDD, J1 16V Tantalum 1210 Capacitor 0.
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LM4941, LM4941SDBD, LM4941TMBD SNAS347C – JUNE 2006 – REVISED MAY 2013 www.ti.com REVISION HISTORY 14 Rev Date Description 1.0 06/28/06 Initial release. 1.1 07/10/06 Added the WSON pkg mktg outline (per Kashif J.) 1.2 08/04/06 Added the WSON package and marking diagrams. 1.3 10/12/06 Edited some of the Typical Performance curves' labels and some text edits. 1.4 10/25/06 Added the WSON boards. 1.5 11/07/06 Text edits. 1.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM4941SD/NOPB Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 2.8 1.0 8.0 12.0 Q1 WSON NGS 8 1000 178.0 12.4 LM4941SDX/NOPB WSON NGS 8 4500 330.0 12.4 3.3 2.8 1.0 8.0 12.0 Q1 LM4941TM/NOPB DSBGA YFQ 9 250 178.0 8.4 1.35 1.35 0.76 4.0 8.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4941SD/NOPB WSON NGS 8 1000 210.0 185.0 35.0 LM4941SDX/NOPB WSON NGS 8 4500 367.0 367.0 35.0 LM4941TM/NOPB DSBGA YFQ 9 250 210.0 185.0 35.0 LM4941TMX/NOPB DSBGA YFQ 9 3000 210.0 185.0 35.
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MECHANICAL DATA NGS0008C SDA08C (Rev A) www.ti.
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MECHANICAL DATA YFQ0009xxx D 0.600±0.075 E TMD09XXX (Rev A) D: Max = 1.24 mm, Min = 1.18 mm E: Max = 1.24 mm, Min = 1.18 mm 4215077/A NOTES: A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994. B. This drawing is subject to change without notice. www.ti.
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