NSC LME49740

LME49740
Quad High Performance, High Fidelity Audio Operational
Amplifier
General Description
Key Specifications
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 operational amplifiers deliver superior audio signal amplification for
outstanding audio performance. The LME49740 combines
extremely low voltage noise density (2.7nV/√HZ) with vanishingly low THD+N (0.00003%) to easily satisfy the most
demanding audio applications. To ensure that the most challenging loads are driven without compromise, the LME49740
has a high slew rate of ±20V/μs and an output current capability 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 amplifier DC performance.
The LME49740 has a wide supply range of ±2.5V to ±17V.
Over this supply range the LME49740’s input circuitry maintains 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.
■ Power Supply Voltage Range
■ THD+N (AV = 1, VOUT = 3VRMS,
fIN = 1kHz)
202105
RL = 2kΩ
0.00003% (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
■
■
■
■
■
■
■
■
■
© 2007 National Semiconductor Corporation
±2.5V to ±17V
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
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LME49740 Quad High Performance, High Fidelity Audio Operational Amplifier
February 2007
LME49740
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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2
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
2000V
200V
150°C
θJA (MA)
Power Supply Voltage
(VS = V+ - V-)
Storage Temperature
Input Voltage
θJA (NA)
Temperature Range
36V
−65°C to 150°C
Output Short Circuit (Note 3)
Power Dissipation
(V-) - 0.7V to (V+) + 0.7V
Continuous
Internally Limited
Electrical Characteristics
(Notes 1, 2)
107°C/W
74°C/W
TMIN ≤ TA ≤ TMAX
Supply Voltage Range
–40°C ≤ TA ≤ 85°C
±2.5V ≤ VS ≤ ± 17V
The following specifications apply for VS = ±15V, RL = 2kΩ, fIN = 1kHz,
and TA = 25C, unless otherwise specified.
LME49740
Symbol
Parameter
Conditions
Typical
Limit
(Note 6)
(Notes 7, 8)
AV = 1, VOUT = 3VRMS
THD+N
Total Harmonic Distortion + Noise
RL = 2kΩ
0.00003
0.00003
RL = 600Ω
AV = 1, VOUT = 3VRMS
Two-tone, 60Hz & 7kHz 4:1
0.00009
0.00005
Units
(Limits)
% (max)
% (max)
IMD
Intermodulation Distortion
% (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
ts
Settling time
AV = 1, 10V step, CL = 100pF
0.1% error range
1.2
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
in
Current Noise Density
f = 1kHz
f = 10Hz
1.6
3.1
nV/√Hz
nV/√Hz
pA/√Hz
pA/√Hz
VOS
Offset Voltage
±0.7
mV (max)
en
10
±0.1
Average Input Offset Voltage Drift vs
ΔVOS/ΔTemp
40°C ≤ TA ≤ 85°C
Temperature
Average Input Offset Voltage Shift vs
ΔVS = 20V (Note 9)
Power Supply Voltage
ISOCH-CH
Channel-to-Channel Isolation
fIN = 1kHz
fIN = 20kHz
118
112
IB
Input Bias Current
VCM = 0V
10
ΔIOS/ΔTemp
Input Bias Current Drift vs
Temperature
–40°C ≤ TA ≤ 85°C
0.1
IOS
Input Offset Current
VCM = 0V
Common-Mode Input Voltage Range
CMRR
Common-Mode Rejection
ZIN
AVOL
–10V<VCM<10V
Differential Input Impedance
Common Mode Input Impedance
Open Loop Voltage Gain
μs
μV/°C
0.2
PSRR
VIN-CM
MHz
120
110
dB (min)
dB
dB
72
nA (max)
nA/°C
11
65
nA (max)
+14.1
–13.9
(V+)–2.0
(V-)+2.0
V (min)
V (min)
120
110
dB (min)
30
kΩ
–10V<VCM<10V
1000
MΩ
–10V<VOUT<10V, RL = 600Ω
140
dB (min)
–10V<VOUT<10V, RL = 2kΩ
140
dB (min)
–10V<VOUT<10V, RL = 10kΩ
140
3
125
dB (min)
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LME49740
ESD Susceptibility (Note 4)
ESD Susceptibility (Note 5)
Junction Temperature
Thermal Resistance
Absolute Maximum Ratings (Notes 1, 2)
LME49740
LME49740
Symbol
Typical
Limit
(Note 6)
(Notes 7, 8)
RL = 600Ω
±13.6
±12.5
RL = 2kΩ
±14.0
RL = 10kΩ
±14.1
Parameter
Conditions
VOUTMAX
Maximum Output Voltage Swing
IOUT
Output Current
IOUT-CC
Short Circuit Current
ROUT
Output Impedance
fIN = 10kHz
Closed-Loop
Open-Loop
CLOAD
Capacitive Load Drive Overshoot
100pF
IS
Total Quiescent Current
IOUT = 0mA
RL = 600Ω, VS = ±17V
±26
Units
(Limits)
V (min)
V (min)
V (min)
±23
mA (min)
+30
–38
mA
mA
0.01
13
Ω
Ω
16
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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4
LME49740
Typical Performance Characteristics
THD+N vs Output Voltage
VCC = 15V, VEE = –15V, RL = 2kΩ
THD+N vs Output Voltage
VCC = 17V, VEE = –17V, RL = 2kΩ
20210515
20210516
THD+N vs Frequency
VCC = 15V, VEE = –15V, RL = 2kΩ, VOUT = 3VRMS
THD+N vs Frequency
VCC = 17V, VEE = –17V, RL = 2kΩ, VOUT = 3VRMS
20210511
20210513
THD+N vs Frequency
VCC = 15V, VEE = –15V, RL = 600Ω, VOUT = 3VRMS
THD+N vs Frequency
VCC = 17V, VEE = –17V, RL = 600Ω, VOUT = 3VRMS
20210514
20210512
5
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LME49740
IMD vs Output Voltage
VCC = 15V, VEE = –15V, RL = 2kΩ
IMD vs Output Voltage
VCC = 17V, VEE = –17V, RL = 2kΩ
20210553
20210554
PSRR+ vs Frequency
VCC = 15V, VEE = –15V,
RL = 2kΩ, VRIPPLE = 200mVpp
PSRR- vs Frequency
VCC = 15V, VEE = –15V, RL = 2kΩ
RL = 2kΩ, VRIPPLE = 200mVpp
20210559
20210560
CMRR vs Frequency
VCC = 15V, VEE = –15V, RL = 2kΩ
Crosstalk vs Frequency
VCC = 15V, VEE = –15V, RL = 2kΩ
20210552
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20210519
6
LME49740
Output Voltage vs Supply Voltage
RL = 2kΩ, THD+N = 1%
Output Voltage vs Load Resistance
THD+N = 1%
20210517
20210518
Supply Current vs Supply Voltage
RL = 2kΩ, THD+N = 1%
Full Power Bandwidth vs Frequency
20210520
20210507
Gain Phase vs Frequency
Voltage Noise Density vs Frequency
20210557
20210551
7
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LME49740
Small-Signal Transient Response
AV = 1, CL = 100pF
Large-Signal Transient Response
AV = 1, CL = 100pF
20210556
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20210555
8
DISTORTION MEASUREMENTS
The vanishingly low residual distortion produced by
LME49740 is below the capabilities of all commercially available equipment. This makes distortion measurements just
slightly more difficult than simply connecting a distortion meter to the amplifier’s inputs and outputs. The solution, however, 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
20210562
FIGURE 2. THD+N and IMD Distortion Test Circuit
9
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LME49740
inputs changes the amplifier’s noise gain. The result is that
the error signal (distortion) is amplified by a factor of 101. Although the amplifier’s closed-loop gain is unaltered, the feedback 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 components that are within the measurement equipment’s capabilities. This datasheet’s THD+N and IMD values were generated using the above described circuit connected to an Audio
Precision System Two Cascade.
Application Information
LME49740
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 prevent excess power dissipation if the output is accidentally
shorted.
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.
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
Flat Amp Voltage Gain vs Frequency
VO = 0dB, AV = 80.0dB, f = 1kHz
20210529
20210528
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NAB Preamp
NAB Preamp Voltage Gain vs Frequency
VIN = 10mV, AV = 34.5dB, f = 1kHz
20210530
AV = 34.5
F = 1 kHz
En = 0.38 μV
A Weighted
20210531
Balanced to Single Ended Converter
Adder/Subtracter
20210533
VO = V1 + V2 − V3 − V4
20210532
VO = V1–V2
Sine Wave Oscillator
20210534
11
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LME49740
Typical Applications
LME49740
Second Order High Pass Filter
(Butterworth)
Second Order Low Pass Filter
(Butterworth)
20210535
20210536
Illustration is f0 = 1 kHz
Illustration is f0 = 1 kHz
State Variable Filter
20210537
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12
LME49740
AC/DC Converter
20210538
2 Channel Panning Circuit (Pan Pot)
Line Driver
20210540
20210539
Tone Control
20210541
13
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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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14
LME49740
Balanced Input Mic Amp
20210543
Illustration is:
V0 = 101(V2 − V1)
15
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LME49740
10 Band Graphic Equalizer
20210544
fo (Hz)
C1
C2
R1
R2
32
0.12μF
4.7μF
75kΩ
500Ω
64
0.056μF
3.3μF
68kΩ
510Ω
125
0.033μF
1.5μF
62kΩ
510Ω
250
0.015μF
8200pF
0.82μF
68kΩ
470Ω
500
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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16
LME49740
Revision History
Rev
Date
1.0
02/28/07
17
Description
Initial WEB release.
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LME49740
Physical Dimensions inches (millimeters) unless otherwise noted
Dual-In-Line Package
Order Number LME49740MA
NS Package Number M14A
Dual-In-Line Package
Order Number LME49740NA
NS Package Number N14A
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LME49740
19
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LME49740 Quad High Performance, High Fidelity Audio Operational Amplifier
Notes
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