Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Audio amplifier 1-channel (mono) with mono headphones Class AB SOIC 8

LM4875

www.ti.com

SNAS042C –JANUARY 2002–REVISED MAY 2013

LM4875 750 mW Audio Power Amplifier with DC Volume

Control and Headphone Switch

Check for Samples: LM4875

FEATURES

DESCRIPTION

The LM4875 is a mono bridged audio power amplifier

• Precision DC Voltage Volume Control

with DC voltage volume control. The LM4875 is

• Headphone Amplifier Mode

capable of delivering 750mW of continuous average

• “Click and Pop” Suppression

power into an 8Ω load with less than 1% THD when

• Shutdown Control When Volume Control Pin Is

bridged speaker mode and headphone (single ended)

Low

mode is accomplished using the headphone sense

• Thermal Shutdown Protection

pin. To conserve power in portable applications, the

LM4875's micropower shutdown mode (I

= 0.7µA,

APPLICATIONS

typ) is activated when less than 300mV is applied to

the DC Vol/SD pin.

• GSM Phones and Accessories, DECT, Office

Phones

Boomer audio power amplifiers are designed

specifically to provide high power audio output while

• Hand Held Radio

maintaining high fidelity. They require few external

• Other Portable Audio Devices

components and operate on low supply voltages.

KEY SPECIFICATIONS

• P

at 1.0% THD+N Into 8Ω; 750 mW (typ)

• P

at 10% THD+N Into 8Ω; 1 W (typ)

• Shutdown Current; 0.7µA(typ)

• Supply Voltage Range; 2.7V to 5.5 V

TYPICAL APPLICATION

CONNECTION DIAGRAM

Small Outline Package (SOIC)

Mini Small Outline Package (VSSOP)

Top View

See Package Number D, DGK

Figure 1. Typical Audio Amplifier Application

Circuit

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)

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LM4875 www.ti.com LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 750 mW Audio Power Amplifier with DC Volume Control and Headphone Switch Check for Samples: LM4875 FEATURES DESCRIPTION • • • • The LM4875 is a mono bridged audio power amplifier with DC voltage volume control. The LM4875 is capable of delivering 750mW of continuous average power into an 8Ω load with less than 1% THD when powered by a 5V power supply.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com 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 Storage Temperature −0.3V to VDD +0.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS (1) (2) The following specifications apply for VDD = 5V, unless otherwise specified. Limits apply for TA = 25°C. Symbol Parameter VDD Conditions Supply Voltage Typical (4) Max (3) Units 5.5 V VIN = 0V, IO = 0A, HP Sense = 0V 4 7 mA VIN = 0V, IO - 0A, HP Sense = 5V 3.5 6 mA 0.7 50 mV Quiescent Power Supply Current ISD Shutdown Current VPIN4 ≤ 0.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS 4 THD+N vs Frequency THD+N vs Frequency Figure 2. Figure 3. THD+N vs Output Power THD+N vs Output Power Figure 4. Figure 5. THD+N vs Output Power THD+N vs Output Power Figure 6. Figure 7.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Power Dissipation vs Load Resistance Power Dissipation vs Output Power Figure 8. Figure 9. Power Derating Curve Clipping Voltage vs RL Figure 10. Figure 11. Noise Floor Frequency Response vs Input Capacitor Size Figure 12. Figure 13.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 6 Power Supply Rejection Ratio Attenuation Level vs DC-Vol Amplitude Figure 14. Figure 15. THD+N vs Frequency THD+N vs Frequency Figure 16. Figure . THD+N vs Frequency THD+N vs Output Power Figure 17. Figure 18.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) THD+N vs Output Power THD+N vs Output Power Figure 19. Figure 20. Output Power vs Load Resistance Clipping Voltage vs Supply Voltage Figure 21. Figure 22. Output Power vs Supply Voltage Figure 23.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 8 Output Power vs Supply Voltage Supply Current vs Supply Voltage Figure 24. Figure 25.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 APPLICATION INFORMATION BRIDGE CONFIGURATION EXPLANATION As shown in Figure 1, the LM4875 consists of two operational amplifiers internally. An external DC voltage sets the closed-loop gain of the first amplifier, whereas two internal 20kΩ resistors set the second amplifier's gain at 1. The LM4875 can be used to drive a speaker connected between the two amplifier outputs or a monaural headphone connected between VO1 and GND.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com POWER SUPPLY BYPASSING As with any power amplifier, proper supply bypassing is critical for low noise performance and high power supply rejection. The capacitors connected to the bypass and power supply pins should be placed as close to the LM4875 as possible. The capacitor connected between the bypass pin and ground improves the internal bias voltage's stability, producing improved PSRR.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 HP-Sense FUNCTION Applying a voltage between 4V and VCC to the LM4875's HP-Sense headphone control pin turns off Amp2 and mutes a bridged-connected load. Quiescent current consumption is reduced when the IC is in this single-ended mode. Figure 27 shows the implementation of the LM4875's headphone control function.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com As the volume changes from minimum to maximum, RIN decrease from 110kΩ to 10kΩ. Equation 4 reveals that the -3dB frequency will increase as the volume increases. The nominal value of Ci for lowest desired frequency response should be calculated with RIN = 10kΩ . As an example when using a speaker with a low frequency limit of 150Hz, Ci, using Equation 4 is 0.1µF. The 0.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 Figure 28. Recommended SOIC PC Board Layout: Component Side Silkscreen Figure 29. Recommended SOIC PC Board Layout: Component Side Layout Figure 30.
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LM4875 SNAS042C – JANUARY 2002 – REVISED MAY 2013 www.ti.com Figure 31. Recommended VSSOP PC Board Layout: Component Side Silkscreen Figure 32. Recommended VSSOP PC Board Layout: Component Side Layout Figure 33.
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LM4875 www.ti.com SNAS042C – JANUARY 2002 – REVISED MAY 2013 REVISION HISTORY Changes from Revision B (May 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-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 LM4875MM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM4875MX/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-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4875MM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM4875MX/NOPB SOIC D 8 2500 367.0 367.0 35.
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