LME49740MABD - National Semiconductor

February 8, 2008

LME49740

Quad High Performance, High Fidelity Audio Operational

Amplifier

General Description

The LME49740 is part of the ultra-low distortion, low noise,

high slew rate operational amplifier series optimized and fully

specified for high performance, high fidelity applications.

Combining advanced leading-edge process technology with

state-of-the-art circuit design, the LME49740 audio opera-

tional amplifiers deliver superior audio signal amplification for

outstanding audio performance. The LME49740 combines

extremely low voltage noise density (2.7nV/√HZ) with van-

ishingly low THD+N (0.00003%) to easily satisfy the most

demanding audio applications. To ensure that the most chal-

lenging loads are driven without compromise, the LME49740

has a high slew rate of ±20V/μs and an output current capa-

bility of ±26mA. Further, dynamic range is maximized by an

output stage that drives 2kΩ loads to within 1V of either power

supply voltage and to within 1.4V when driving 600Ω loads.

The LME49740's outstanding CMRR(120dB), PSRR(120dB),

and VOS(0.1mV) give the amplifier excellent operational am-

plifier DC performance.

The LME49740 has a wide supply range of ±2.5V to ±17V.

Over this supply range the LME49740’s input circuitry main-

tains excellent common-mode and power supply rejection, as

well as maintaining its low input bias current. The LME49740

is unity gain stable. The Audio Operational Amplifier achieves

outstanding AC performance while driving complex loads with

values as high as 100pF.

The LME49740 is available in 14–lead narrow body SOIC and

14–lead plastic DIP. Demonstration boards are available for

each package.

Key Specifications

■ Power Supply Voltage Range ±2.5V to ±17V

■ THD+N (AV = 1, VOUT = 3VRMS,

fIN = 1kHz)

RL = 2kΩ0.00003% (typ)

RL = 600Ω 0.00003% (typ)

■ Input Noise Density 2.7nV/√Hz (typ)

■ Slew Rate ±20V/μs (typ)

■ Gain Bandwidth Product 55MHz (typ)

■ Open Loop Gain (RL = 600Ω) 140dB (typ)

■ Input Bias Current 10nA (typ)

■ Input Offset Voltage 0.1mV (typ)

■ DC Gain Linearity Error 0.000009%

Features

■Easily drives 600Ω loads

■Optimized for superior audio signal fidelity

■Output short circuit protection

■PSRR and CMRR exceed 120dB (typ)

■SOIC and DIP packages

Applications

■Ultra high quality audio amplification

■High fidelity preamplifiers

■High fidelity multimedia

■State of the art phono pre amps

■High performance professional audio

■High fidelity equalization and crossover networks

■High performance line drivers

■High performance line receivers

■High fidelity active filters

LME49740 Quad High Performance, High Fidelity Audio Operational Amplifier

Typical Application

20210502

FIGURE 1. Passively Equalized RIAA Phono Preamplifier

Connection Diagram

20210501

Order Number LME49740MA

See NS Package Number — M14A

Order Number LME49740NA

See NS Package Number — N14A

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LME49740

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.

Power Supply Voltage

(VS = V+ - V-)36V

Storage Temperature −65°C to 150°C

Input Voltage (V-) - 0.7V to (V+) + 0.7V

Output Short Circuit (Note 3) Continuous

Power Dissipation Internally Limited

ESD Susceptibility (Note 4) 2000V

ESD Susceptibility (Note 5) 200V

Junction Temperature 150°C

Thermal Resistance

θJA (MA) 107°C/W

θJA (NA) 74°C/W

Temperature Range

TMIN ≤ TA ≤ TMAX –40°C ≤ TA ≤ 85°C

Supply Voltage Range ±2.5V ≤ VS ≤ ± 17V

Electrical Characteristics (Notes 1, 2) The following specifications apply for VS = ±15V, RL = 2kΩ, fIN = 1kHz,

and TA = 25C, unless otherwise specified.

Symbol Parameter Conditions

LME49740 Units

(Limits)

Typical Limit

(Note 6) (Notes 7, 8)

THD+N Total Harmonic Distortion + Noise

AV = 1, VOUT = 3VRMS

RL = 2kΩ

RL = 600Ω

0.00003

0.00003 0.00009

% (max)

IMD Intermodulation Distortion AV = 1, VOUT = 3VRMS

Two-tone, 60Hz & 7kHz 4:1 0.00005 % (max)

GBWP Gain Bandwidth Product 55 45 MHz (min)

SR Slew Rate ±20 ±15 V/μs (min)

FPBW Full Power Bandwidth

VOUT = 1VP-P, –3dB

referenced to output magnitude

at f = 1kHz

MHz

tsSettling time AV = 1, 10V step, CL = 100pF

0.1% error range 1.2

μs

Equivalent Input Noise Voltage fBW = 20Hz to 20kHz 0.34 0.65 μVRMS

Equivalent Input Noise Density f = 1kHz

f = 10Hz

2.7

6.4

4.7 nV/√Hz

nV/√Hz

inCurrent Noise Density f = 1kHz

f = 10Hz

1.6

3.1

pA/√Hz

VOS Offset Voltage ±0.1 ±0.7 mV (max)

ΔVOS/ΔTemp Average Input Offset Voltage Drift vs

Temperature 40°C ≤ TA ≤ 85°C 0.2 μV/°C

PSRR Average Input Offset Voltage Shift vs

Power Supply Voltage ΔVS = 20V (Note 9) 120 110 dB (min)

ISOCH-CH Channel-to-Channel Isolation fIN = 1kHz

fIN = 20kHz

118

112

IBInput Bias Current VCM = 0V 10 72 nA (max)

ΔIOS/ΔTemp Input Bias Current Drift vs

Temperature –40°C ≤ TA ≤ 85°C 0.1 nA/°C

IOS Input Offset Current VCM = 0V 11 65 nA (max)

VIN-CM Common-Mode Input Voltage Range +14.1

–13.9

(V+)–2.0

(V-)+2.0

V (min)

CMRR Common-Mode Rejection –10V<VCM<10V 120 110 dB (min)

ZIN

Differential Input Impedance 30 kΩ

Common Mode Input Impedance –10V<VCM<10V 1000 MΩ

AVOL Open Loop Voltage Gain

–10V<VOUT<10V, RL = 600Ω 140 dB (min)

–10V<VOUT<10V, RL = 2kΩ140 dB (min)

–10V<VOUT<10V, RL = 10kΩ140 125 dB (min)

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LME49740

Symbol Parameter Conditions

LME49740 Units

(Limits)

Typical Limit

(Note 6) (Notes 7, 8)

VOUTMAX Maximum Output Voltage Swing

RL = 600Ω ±13.6 ±12.5 V (min)

RL = 2kΩ±14.0 V (min)

RL = 10kΩ±14.1 V (min)

IOUT Output Current RL = 600Ω, VS = ±17V ±26 ±23 mA (min)

IOUT-CC Short Circuit Current +30

–38

ROUT Output Impedance

fIN = 10kHz

Closed-Loop

Open-Loop

0.01

Ω

CLOAD Capacitive Load Drive Overshoot 100pF 16 %

ISTotal Quiescent Current IOUT = 0mA 18.5 20 mA (max)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 2: Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications

and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics

may degrade when the device is not operated under the listed test conditions.

Note 3: Amplifier output connected to GND, any number of amplifiers within a package.

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

Note 5: Machine Model ESD test is covered by specification EIAJ IC-121-1981. A 200pF cap is charged to the specified voltage and then discharged directly into

the IC with no external series resistor (resistance of discharge path must be under 50Ω).

Note 6: Typical specifications are specified at +25ºC and represent the most likely parametric norm.

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

Note 8: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

Note 9: PSRR is measured as follows: VOS is measured at two supply voltages, ±5V and ±15V. PSRR = |20log(ΔVOS/ΔVS)|.

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LME49740

Typical Performance Characteristics

THD+N vs Output Voltage

VCC = 15V, VEE = –15V, RL = 2kΩ

20210515

THD+N vs Output Voltage

VCC = 17V, VEE = –17V, RL = 2kΩ

20210516

THD+N vs Frequency

VCC = 15V, VEE = –15V, RL = 2kΩ, VOUT = 3VRMS

20210511

THD+N vs Frequency

VCC = 17V, VEE = –17V, RL = 2kΩ, VOUT = 3VRMS

20210513

THD+N vs Frequency

VCC = 15V, VEE = –15V, RL = 600Ω, VOUT = 3VRMS

20210512

THD+N vs Frequency

VCC = 17V, VEE = –17V, RL = 600Ω, VOUT = 3VRMS

20210514

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LME49740

IMD vs Output Voltage

VCC = 15V, VEE = –15V, RL = 2kΩ

20210553

IMD vs Output Voltage

VCC = 17V, VEE = –17V, RL = 2kΩ

20210554

PSRR+ vs Frequency

VCC = 15V, VEE = –15V,

RL = 2kΩ, VRIPPLE = 200mVpp

20210559

PSRR- vs Frequency

VCC = 15V, VEE = –15V, RL = 2kΩ

RL = 2kΩ, VRIPPLE = 200mVpp

20210560

CMRR vs Frequency

VCC = 15V, VEE = –15V, RL = 2kΩ

20210552

Crosstalk vs Frequency

VCC = 15V, VEE = –15V, RL = 2kΩ

20210519

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LME49740

Output Voltage vs Supply Voltage

RL = 2kΩ, THD+N = 1%

20210518

Output Voltage vs Load Resistance

THD+N = 1%

20210517

Supply Current vs Supply Voltage

RL = 2kΩ, THD+N = 1%

20210507

Full Power Bandwidth vs Frequency

20210520

Gain Phase vs Frequency

20210551

Voltage Noise Density vs Frequency

20210557

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LME49740

Small-Signal Transient Response

AV = 1, CL = 100pF

20210556

Large-Signal Transient Response

AV = 1, CL = 100pF

20210555

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LME49740

Application Information

DISTORTION MEASUREMENTS

The vanishingly low residual distortion produced by

LME49740 is below the capabilities of all commercially avail-

able equipment. This makes distortion measurements just

slightly more difficult than simply connecting a distortion me-

ter to the amplifier’s inputs and outputs. The solution, how-

ever, is quite simple: an additional resistor. Adding this

resistor extends the resolution of the distortion measurement

equipment.

The LME49740’s low residual distortion is an input referred

internal error. As shown in Figure 2, adding the 10Ω resistor

connected between the amplifier’s inverting and non-inverting

inputs changes the amplifier’s noise gain. The result is that

the error signal (distortion) is amplified by a factor of 101. Al-

though the amplifier’s closed-loop gain is unaltered, the feed-

back available to correct distortion errors is reduced by 101,

which means that measurement resolution increases by 101.

To ensure minimum effects on distortion measurements,

keep the value of R1 low as shown in Figure 2.

This technique is verified by duplicating the measurements

with high closed loop gain and/or making the measurements

at high frequencies. Doing so produces distortion compo-

nents that are within the measurement equipment’s capabili-

ties. This datasheet’s THD+N and IMD values were generat-

ed using the above described circuit connected to an Audio

Precision System Two Cascade.

20210562

FIGURE 2. THD+N and IMD Distortion Test Circuit

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LME49740

Application Hints

The LME49740 is a high speed op amp with excellent phase

margin and stability. Capacitive loads up to 100pF will cause

little change in the phase characteristics of the amplifiers and

are therefore allowable.

Capacitive loads greater than 100pF must be isolated from

the output. The most straightforward way to do this is to put

a resistor in series with the output. This resistor will also pre-

vent excess power dissipation if the output is accidentally

shorted.

Noise Measurement Circuit

20210527

Complete shielding is required to prevent induced pick up from external sources. Always check with oscilloscope for power line noise.

Total Gain: 115 dB at f = 1 kHz

Input Referred Noise Voltage: en = VO/560,000 (V)

RIAA Preamp Voltage Gain,

RIAA Deviation vs Frequency

VIN = 10mV, AV = 35.0dB, f = 1kHz

20210528

Flat Amp Voltage Gain vs Frequency

VO = 0dB, AV = 80.0dB, f = 1kHz

20210529

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LME49740

Typical Applications

NAB Preamp

20210530

AV = 34.5

F = 1 kHz

En = 0.38 μV

A Weighted

NAB Preamp Voltage Gain vs Frequency

VIN = 10mV, AV = 34.5dB, f = 1kHz

20210531

Balanced to Single Ended Converter

20210532

VO = V1–V2

Adder/Subtracter

20210533

VO = V1 + V2 − V3 − V4

Sine Wave Oscillator

20210534

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LME49740

Second Order High Pass Filter

(Butterworth)

20210535

Illustration is f0 = 1 kHz

Second Order Low Pass Filter

(Butterworth)

20210536

Illustration is f0 = 1 kHz

State Variable Filter

20210537

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LME49740

AC/DC Converter

20210538

2 Channel Panning Circuit (Pan Pot)

20210539

Line Driver

20210540

Tone Control

20210541

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LME49740

20210542

RIAA Preamp

20210503

Av = 35 dB

En = 0.33 μV

S/N = 90 dB

f = 1 kHz

A Weighted

A Weighted, VIN = 10 mV

@f = 1 kHz

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LME49740

Balanced Input Mic Amp

20210543

Illustration is:

V0 = 101(V2 − V1)

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LME49740

10 Band Graphic Equalizer

20210544

fo (Hz) C1C2R1R2

32 0.12μF4.7μF 75kΩ 500Ω

64 0.056μF3.3μF 68kΩ 510Ω

125 0.033μF1.5μF 62kΩ 510Ω

250 0.015μF0.82μF 68kΩ 470Ω

500 8200pF 0.39μF 62kΩ 470Ω

1k 3900pF 0.22μF 68kΩ 470Ω

2k 2000pF 0.1μF 68kΩ 470Ω

4k 1100pF 0.056μF 62kΩ 470Ω

8k 510pF 0.022μF 68kΩ 510Ω

16k 330pF 0.012μF 51kΩ 510Ω

Note 10: At volume of change = ±12 dB

Q = 1.7

Reference: “AUDIO/RADIO HANDBOOK”, National Semiconductor, 1980, Page 2–61

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LME49740

Revision History

Rev Date Description

1.0 02/28/07 Initial WEB release.

1.01 02/08/08 Fixed the captions on the LME4970MA package (from Dual-In-

Line to Molded Package (SO).

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LME49740

Physical Dimensions inches (millimeters) unless otherwise noted

Molded Package (SO)

Order Number LME49740MA

NS Package Number M14A

Dual-In-Line Package

Order Number LME49740NA

NS Package Number N14A

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LME49740

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LME49740

Notes

LME49740 Quad High Performance, High Fidelity Audio Operational Amplifier

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