Datasheet

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LM2876

www.ti.com

SNAS088C –AUGUST 1995–REVISED MARCH 2013

LM2876 Overture™ Audio Power Amplifier Series

High-Performance 40W Audio Power Amplifier w/Mute

Check for Samples: LM2876

FEATURES

DESCRIPTION

The LM2876 is a high-performance audio power

• 40W Continuous Average Output Power Into

amplifier capable of delivering 40W of continuous

8Ω

average power to an 8Ω load with 0.1% THD+N from

• 75W Instantaneous Peak Output Power

20Hz–20kHz.

Capability

The performance of the LM2876, utilizing its Self

• Signal-to-Noise Ratio ≥ 95 dB(min)

Peak Instantaneous Temperature (°Ke) (SPiKe)

• An Input Mute Function

protection circuitry, puts it in a class above discrete

and hybrid amplifiers by providing an inherently,

• Output Protection From A Short to Ground Or

dynamically protected Safe Operating Area (SOA).

to the Supplies Via Internal Current Limiting

SPiKe protection means that these parts are

Circuitry

completely safeguarded at the output against

• Output Over-Voltage Protection Against

overvoltage, undervoltage, overloads, including shorts

Transients From Inductive Loads

to the supplies, thermal runaway, and instantaneous

temperature peaks.

• Supply Under-Voltage Protection, Not Allowing

Internal Biasing to Occur When |V

| + |V

| ≤

The LM2876 maintains an excellent signal-to-noise

12V, Thus Eliminating Turn-On and Turn-Off

ratio of greater than 95dB (min) with a typical low

Transients

noise floor of 2.0μV. It exhibits extremely low THD+N

values of 0.06% at the rated output into the rated

• 11-Lead PFM Package

load over the audio spectrum, and provides excellent

• Wide Supply Range 20V - 72V

linearity with an IMD (SMPTE) typical rating of

0.004%.

APPLICATIONS

• Component Stereo

• Compact Stereo

• Self-Powered Speakers

• Surround-Sound Amplifiers

• High-End Stereo TVs

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.

2Overture is a trademark of Texas Instruments.

3All other 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 (28 pages)

PAGE 1
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 LM2876 Overture™ Audio Power Amplifier Series High-Performance 40W Audio Power Amplifier w/Mute Check for Samples: LM2876 FEATURES DESCRIPTION • The LM2876 is a high-performance audio power amplifier capable of delivering 40W of continuous average power to an 8Ω load with 0.1% THD+N from 20Hz–20kHz.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com Typical Application * Optional components dependent upon specific design requirements. Refer to the External Components Description section for a component functional description. Figure 1. Typical Audio Amplifier Application Circuit Connection Diagram †Connect Pin 5 to V+ for Compatibility with LM3886. *Preliminary: Call your local Texas Instruments' sales rep. or distributor for availability. Figure 2.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 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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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 ELECTRICAL CHARACTERISTICS www.ti.com (1) (2) The following specifications apply for V+ = +30V, V− = −30V, IMUTE = −0.5 mA with RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 Test Circuit #1 (DC Electrical Test Circuit) Figure 3. Test Circuit #2 (AC Electrical Test Circuit) Figure 4.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com SINGLE SUPPLY APPLICATION CIRCUIT *Optional components dependent upon specific design requirements. Refer to the External Components Description section for a component functional description. Figure 5.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 Equivalent Schematic (excluding active protection circuitry) Figure 6.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com External Components Description (10) Components Functional Description 1. RIN Acts as a volume control by setting the voltage level allowed to the amplifier's input terminals. 2. RA Provides DC voltage biasing for the single supply operation and bias current for the positive input terminal. 3. CA Provides bias filtering. 4. C Provides AC coupling at the input and output of the amplifier for single supply operation. 5.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS Safe Area SPiKe Protection Response Figure 7. Figure 8. Supply Current vs Supply Voltage Pulse Thermal Resistance Figure 9. Figure 10. Pulse Thermal Resistance Supply Current vs Output Voltage Figure 11. Figure 12.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 10 Pulse Power Limit Pulse Power Limit Figure 13. Figure 14. Supply Current vs Case Temperature Pulse Response Figure 15. Figure 16. Input Bias Current vs Case Temperature Clipping Voltage vs Supply Voltage Figure 17. Figure 18.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) THD + N vs Frequency THD + N vs Output Power Figure 19. Figure 20. THD + N vs Output Power THD + N Distribution Figure 21. Figure 22. THD + N Distribution Output Power vs Load Resistance Figure 23. Figure 24.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Max Heatsink Thermal Resistance (°C/W) at the Specified Ambient Temperature (°C) Maximum Power Dissipation vs Supply Voltage Note: The maximum heat sink thermal resistance values, øSA, in the table above were calculated using a øCS = 0.2°C/W due to thermal compound. Figure 25. 12 Power Dissipation vs Output Power Power Dissipation vs Output Power Figure 26. Figure 27.
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LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) IMD 60 Hz, 7 kHz, 4:1 IMD 60 Hz, 7 kHz, 4:1 Figure 30. Figure 31. IMD 60 Hz, 1:1 IMD 60 Hz, 7 kHz 1:1 Figure 32. Figure 33. IMD 60 Hz, 7 kHz, 1:1 Mute Attenuation vs Mute Current Figure 34. Figure 35.
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LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Mute Attenuation vs Mute Current Large Signal Response Figure 36. Figure 37. Power Supply Rejection Ratio Common-Mode Rejection Ratio Figure 38. Figure 39. Open Loop Frequency Response Figure 40.
PAGE 15
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 APPLICATION INFORMATION GENERAL FEATURES Mute Function The muting function of the LM2876 allows the user to mute the music going into the amplifier by drawing less than 0.5 mA out of pin 8 of the device. This is accomplished as shown in the Typical Application Circuit where the resistor RM is chosen with reference to your negative supply voltage and is used in conjuction with a switch.
PAGE 16
LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com THERMAL CONSIDERATIONS Heat Sinking The choice of a heat sink for a high-power audio amplifier is made entirely to keep the die temperature at a level such that the thermal protection circuitry does not operate under normal circumstances. The heat sink should be chosen to dissipate the maximum IC power for a given supply voltage and rated load.
PAGE 17
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 Determining Maximum Power Dissipation Power dissipation within the integrated circuit package is a very important parameter requiring a thorough understanding if optimum power output is to be obtained. An incorrect maximum power dissipation (PD) calculation may result in inadequate heat sinking, causing thermal shutdown circuitry to operate and limit the output power.
PAGE 18
LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com Equation 1 and Equation 4 are the only equations needed in the determination of the maximum heat sink thermal resistance. This is of course given that the system designer knows the required supply voltages to drive his rated load at a particular power output level and the parameters provided by the semiconductor manufacturer.
PAGE 19
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 SUPPLY BYPASSING The LM2876 has excellent power supply rejection and does not require a regulated supply. However, to eliminate possible oscillations all op amps and power op amps should have their supply leads bypassed with lowinductance capacitors having short leads and located close to the package terminals.
PAGE 20
LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com “Ground Loop” is the term used to describe situations occurring in ground systems where a difference in potential exists between two ground points. Ideally a ground is a ground, but unfortunately, in order for this to be true, ground conductors with zero resistance are necessary. Since real world ground leads possess finite resistance, currents running through them will cause finite voltage drops to exist.
PAGE 21
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 REACTIVE LOADING It is hard for most power amplifiers to drive highly capacitive loads very effectively and normally results in oscillations or ringing on the square wave response. If the output of the LM2876 is connected directly to a capacitor with no series resistance, the square wave response will exhibit ringing if the capacitance is greater than about 0.2 μF.
PAGE 22
LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com DESIGN A 25W/8Ω AUDIO AMPLIFIER Given: Power Output 25W Load Impedance 8Ω Input Level 1V(max) Input Impedance 100 kΩ Bandwidth 20 Hz–20 kHz ± 0.25 dB Equation 5 and Equation 6 give: 25W/8Ω Vopeak = 20.0V Iopeak = 2.5A Therefore the supply required is: ±24.0V @ 2.5A With 15% regulation and high line the final supply voltage is ±30.36V using Equation 7.
PAGE 23
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 Power Supply Rejection: The ratio of the change in input offset voltage to the change in power supply voltages producing it. Quiescent Supply Current: The current required from the power supply to operate the amplifier with no load and the output voltage and current at zero. Slew Rate: The internally limited rate of change in output voltage with a large amplitude step function applied to the input.
PAGE 24
LM2876 SNAS088C – AUGUST 1995 – REVISED MARCH 2013 www.ti.com Power Bandwidth: The power bandwidth of an audio amplifier is the frequency range over which the amplifier voltage gain does not fall below 0.707 of the flat band voltage gain specified for a given load and output power. Power bandwidth also can be measured by the frequencies at which a specified level of distortion is obtained while the amplifier delivers a power output 3 dB below the rated output.
PAGE 25
LM2876 www.ti.com SNAS088C – AUGUST 1995 – REVISED MARCH 2013 REVISION HISTORY Changes from Revision B (March 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
PAGE 26
PACKAGE OPTION ADDENDUM www.ti.com 21-May-2013 PACKAGING INFORMATION Orderable Device Status (1) LM2876TF/NOPB ACTIVE Package Type Package Pins Package Drawing Qty TO-220 NDA 11 20 Eco Plan Lead/Ball Finish (2) Pb-Free (RoHS Exempt) MSL Peak Temp Op Temp (°C) Device Marking (3) CU SN Level-1-NA-UNLIM (4/5) -20 to 85 LM2876TF (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
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MECHANICAL DATA NDA0011B TF11B (Rev D) www.ti.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.