LM3886.pdf

April 1995

LM3886 Audio Power Amplifier Series

High-Performance 68W Audio Power Amplifier w/Mute

General Description

The LM3886 is a high-performance audio power amplifier

capable of delivering 68W of continuous average power to a

4 X load and 38W into 8 X with 0.1% (THD a N) from

20 Hz±20 kHz.

The performance of the LM3886, utilizing its Self Peak In-

stantaneous Temperature ( § Ke) (SPiKe) Protection Circuit-

ry, puts it in a class above discrete and hybrid amplifiers by

providing an inherently, dynamically protected Safe Operat-

ing Area (SOA). SPiKe Protection means that these parts

are completely safeguarded at the output against overvolt-

age, undervoltage, overloads, including shorts to the sup-

plies, thermal runaway, and instantaneous temperature

peaks.

The LM3886 maintains an excellent Signal-to-Noise Ratio of

greater than 92 dB with a typical low noise floor of 2.0 m V. It

exhibits extremely low (THD a N) values of 0.03% at the

rated output into the rated load over the audio spectrum,

and provides excellent linearity with an IMD (SMPTE) typical

rating of 0.004%.

Features

Y 68W cont. avg. output power into 4 X at V CC e g 28V

Y 38W cont. avg. output power into 8 X at V CC e g 28V

Y 50W cont. avg. output power into 8 X at V CC e g 35V

Y 135W instantaneous peak output power capability

Y Signal-to-Noise Ratio t 92 dB

Y An input mute function

Y Output protection from a short to ground or to the

supplies via internal current limiting circuitry

Y Output over-voltage protection against transients from

inductive loads

Y Supply under-voltage protection, not allowing internal

biasing to occur when l V EE l a l V CC l s 12V, thus

eliminating turn-on and turn-off transients

Y 11-lead TO-220 package

Applications

Y Component stereo

Y Compact stereo

Y Self-powered speakers

Y Surround-sound amplifiers

Y High-end stereo TVs

Typical Application

Connection Diagram

Plastic Package (Note 8)

TL/H/11833±2

TL/H/11833±1

Top View

Order Number LM3886T

or LM3886TF

See NS Package Number TA11B for

Staggered Lead Non-Isolated

Package or TF11B* for

Staggered Lead Isolated Package

FIGURE 1. Typical Audio Amplifier Application Circuit

*Optional components dependent upon specific design requirements. Refer to the External Compo-

nents Description section for a component functional description.

*Preliminary: call you local National Sales Rep.

or distributor for availability

Overture TM and SPiKe TM Protection are trademarks of National Semiconductor Corporation.

C 1995 National Semiconductor Corporation

TL/H/11833

RRD-B30M75/Printed in U. S. A.

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales

Office/Distributors for availability and specifications.

Supply Voltage l V a l a l V b l (No Signal)

Soldering Information

T Package (10 seconds)

260 § C

Storage Temperature

b 40 § Cto a 150 § C

94V

Thermal Resistance

i JC

Supply Voltage l V a l a l V b l (Input Signal)

84V

1 § C/W

Common Mode Input Voltage

(V a or V b ) and

l V a l a l V b l s 80V

i JA

43 § C/W

Operating Ratings (Notes 1, 2)

Temperature Range

T MIN s T A s T MAX b 20 § C s T A s a 85 § C

Supply Voltage l V a l a l V b l 20V to 84V

Note: Operation is guaranteed up to 84V, however, distortion may be intro-

duced from SPiKe Protection Circuitry if proper thermal considera-

tions are not taken into account. Refer to the Thermal Considera-

tions section for more information.

(See SPiKe TM Protection Response)

Differential Input Voltage (Note 12)

60V

Output Current

Internally Limited

Power Dissipation (Note 3)

125W

ESD Susceptibility (Note 4)

3000V

Junction Temperature (Note 5)

150 § C

Electrical Characteristics (Notes 1, 2) The following specifications apply for V a ea 28V, V b eb 28V,

I MUTE eb 0.5 mA with R L e 4 X unless otherwise specified. Limits apply for T A e 25 § C.

LM3886

Units

Symbol

Parameter

Conditions

Typical Limit

(Note 6) (Note 7)

(Limits)

l V a l a l V b l Power Supply Voltage (Note 10)

V pin7 b V b t 9V

20 V (min)

84 V (max)

A M

Mute Attenuation

Pin 8 Open or at 0V, Mute: On

Current out of Pin 8 l 0.5 mA,

115

80 dB (min)

Mute: Off

**P O

Output Power (Continuous Average) THD a N e 0.1% (max)

f e 1 kHz; f e 20 kHz

l V a l e l V b l e 28V, R L e 4 X

60 W (min)

l V a l e l V b l e 28V, R L e 8 X

30 W (min)

l V a l e l V b l e 35V, R L e 8 X

Peak P O Instantaneous Peak Output Power

135

THD a N Total Harmonic Distortion Plus Noise 60W, R L e 4 X ,

0.03

30W, R L e 8 X ,

0.03

20 Hz s f s 20 kHz

A V e 26 dB

**SR

Slew Rate (Note 9)

V IN e 2.0Vp-p, t RISE e 2ns

19 8 V/ m s (min)

*I a

Total Quiescent Power Supply Current V CM e 0V, V o e 0V, I o e 0A

85 mA (max)

*V OS

Input Offset Voltage

V CM e 0V, I o e 0 mA

10 mV (max)

I B

Input Bias Current

V CM e 0V, I o e 0 mA

0.2

1 m A (max)

I OS

Input Offset Current

V CM e 0V, I o e 0 mA

0.01

0.2 m A (max)

I o

Output Current Limit

l V a l e l V b l e 20V, t ON e 10 ms, V O e 0V 11.5

7 A (min)

l V a ±V O l ,V a e 28V, I o ea 100 mA

*V od

Output Dropout Voltage (Note 11)

1.6

2.0 V (max)

l V O ±V b l ,V b eb 28V, I o eb 100 mA

2.5

3.0 V (max)

*PSRR Power Supply Rejection Ratio

V a e 40V to 20V, V b eb 40V,

120

85 dB (min)

V CM e 0V, I o e 0mA

V a e 40V, V b eb 40V to b 20V,

105

85 dB (min)

V CM e 0V, I o e 0mA

*DC Electrical Test; refer to Test Circuit Ý1.

**AC Electrical Test; refer to Test Circuit Ý2.

Electrical Characteristics (Notes 1, 2)

The following specifications apply for V a ea 28V, V b eb 28V, I MUTE eb 0.5 mA with R L e 4 X unless otherwise specified.

Limits apply for T A e 25 § C. (Continued)

LM3886

Units

Symbol

Parameter

Conditions

Typical Limit

(Note 6) (Note 7)

(Limits)

*CMRR Common Mode Rejection Ratio V a e 60V to 20V, V b eb 20V to b 60V,

110

dB (min)

V CM e 20V to b 20V, I o e 0mA

*A VOL Open Loop Voltage Gain

l V a l e l V b l e 28V, R L e 2k X , D V O e 40V 115

dB (min)

GBWP Gain-Bandwidth Product

l V a l e l V b l e 30V

2 MHz (min)

f O e 100 kHz, V IN e 50 mVrms

**e IN Input Noise

IHFÐA Weighting Filter

2.0

10 m V (max)

R IN e 600 X (Input Referred)

SNR Signal-to-Noise Ratio

P O e 1W, A-Weighted,

92.5

Measured at 1 kHz, R S e 25 X

P O e 60W, A-Weighted,

110

Measured at 1 kHz, R S e 25 X

IMD Intermodulation Distortion Test 60 Hz, 7 kHz, 4:1 (SMPTE)

0.004

60 Hz, 7 kHz, 1:1 (SMPTE)

0.009

*DC Electrical Test; refer to Test Circuit Ý1.

**AC Electrical Test; refer to Test Circuit Ý2.

Note 1: All voltages are measured with respect to the GND pin (pin 7), unless otherwise specified.

Note 2: AbsoluteMaximumRatings indicate limits beyond which damage to the device may occur. OperatingRatings indicate conditions for which the device is

functional, but do not guarantee specific performance limits. ElectricalCharacteristics state DC and AC electrical specifications under particular test conditions

which guarantee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where

no limit is given, however, the typical value is a good indication of device performance.

Note 3: For operating at case temperatures above 25 § C, the device must be derated based on a 150 § C maximum junction temperature and a thermal resistance of

i JC e 1.0 § C/W (junction to case). Refer to the Thermal Resistance figure in the Application Information section under Thermal Considerations.

Note 4: Human body model, 100 pF discharged through a 1.5 k X resistor.

Note 5: The operating junction temperature maximum is 150 § C, however, the instantaneous Safe Operating Area temperature is 250 § C.

Note 6: Typicals are measured at 25 § C and represent the parametric norm.

Note 7: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).

Note 8: The LM3886T package TA11B is a non-isolated package, setting the tab of the device and the heat sink at V b potential when the LM3886 is directly

mounted to the heat sink using only thermal compound. If a mica washer is used in addition to thermal compound, i CS (case to sink) is increased, but the heat sink

will be isolated from V b .

Note 9: The feedback compensation network limits the bandwidth of the closed-loop response and so the slew rate will be reduced due to the high frequency roll-

off. Without feedback compensation, the slew rate is typically larger.

Note 10: V b must have at least b 9V at its pin with reference to ground in order for the under-voltage protection circuitry to be disabled.

Note 11: The output dropout voltage is the supply voltage minus the clipping voltage. Refer to the Clipping Voltage vs Supply Voltage graph in the Typical

Performance Characteristics section.

Note 12: The Differential Input Voltage Absolute Maximum Rating is based on supply voltages of V a ea 40V and V b eb 40V.

Test Circuit Ý 1 *(DC Electrical Test Circuit)

TL/H/11833±3

Test Circuit Ý 2 **(AC Electrical Test Circuit)

TL/H/11833±4

Single Supply Application Circuit

TL/H/11833±5

FIGURE 2. Typical Single Supply Audio Amplifier Application Circuit

*Optional components dependent upon specific design requirements. Refer to the External

Components Description section for a component functional description.

Equivalent Schematic (excluding active protection circuitry)

TL/H/11833±6

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