LT1115
Ultralow Noise,
Low Distortion, Audio Op Amp
FEATURES
■
■
■
■
■
■
DESCRIPTIO
■
Voltage Noise: 1.2nV/√Hz Max at 1kHz
0.9nV/√Hz Typ at 1kHz
Voltage and Current Noise 100% Tested
Gain-Bandwidth Product: 40MHz Min
Slew Rate: 10V/µs Min
Voltage Gain: 2 Million Min
Low THD at 10kHz, A
V
= –10, R
L
= 600Ω: 0.002%
V
O
= 7V
RMS
Low IMD, CCIF Method, A
V
= +10: 0.002%
R
L
= 600Ω
V
O
= 7V
RMS
The LT
®
1115 is the lowest noise audio operational ampli-
fier available. This ultralow noise performance (0.9nV/√Hz
at 1kHz) is combined with high slew rates (>15V/µs) and
very low distortion specifications.
The RIAA circuit shown below using the LT1115 has very
low distortion and little deviation from ideal RIAA
response (see graph).
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
■
■
■
■
■
■
■
High Quality Audio Preamplifiers
Low Noise Microphone Preamplifiers
Very Low Noise Instrumentation Amplifiers
Low Noise Frequency Synthesizers
Infrared Detector Amplifiers
Hydrophone Amplifiers
Low Distortion Oscillators
TYPICAL APPLICATIO
18V
RIAA Phonograph Preamplifier (40/60db Gain)
18V
+
INPUT
R
IN
47.5k (MM)
100Ω (MC)
COM
C
IN
(SELECT
PER
PHOTO
CART-
RIDGE)
3
+
–
7
6
1µF
35V
+
1µF
35V
100Ω
2N4304*
~250Ω
SELECT
FOR 2mA
1
2
A2
LT1010CT
3
R
BOOST
49.9Ω
4
5
562Ω
OUTPUT
3900pF
2
A1
LT1115
4
2mA
1µF
35V
R
L
25k
V
+
499Ω
18V
17.8k
330pF
+
COM
470µF
35V
22.6Ω
+
V
–
470µF
35V
–18V
210Ω
SINGLE
POINT
BOARD
GROUND
OPEN—MM
CLOSED—MC
82.5k
4.7µF
FILM
3900pF
+
2200µF
16V
NOTE: BYPASS SUPPLIES WITH LOW ESR CAPS
OTHER CAPS: HIGH QUALITY FILM
+
+
–18V
1µF
35V
DEVIATION (dB)
–18V
210k
15nF
RESISTORS 1%
*OR USE 2mA CURRENT SOURCE
MM = MOVING MAGNET
MC = MOVING COIL
LT1115 • TA01
U
Measured Deviation from RIAA
Response. lnput at 1kHz = 1mV
RMS
Pre-Emphasized
1.0000
0.80000
0.60000
0.40000
0.20000
0.0
–0.2000
–0.4000
–0.6000
–0.8000
–1.000
20
100
1k
FREQUENCY (Hz)
10k
50k
LT1115 • TA02
U
U
V
S
=
±
18V
R
S
= 25Ω
T
A
= 25
°
C
MEASURED
COMPUTER
SIMULATED
1115fa
1
LT1115
ABSOLUTE
(Note 1)
AXI U
RATI GS
Operating Temperature Range ..................... 0°C to 70°C
Storage Temperature Range ..................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Supply Voltage ......................................................
±22V
Differential Input Current (Note 5) ......................
±25mA
Input Voltage ............................ Equal to Supply Voltage
Output Short-Circuit Duration .......................... Indefinite
PACKAGE DESCRIPTIO
TOP VIEW
V
OS
TRIM 1
–IN 2
+IN 3
V
–
4
V
8
OS
TRIM
7 V
+
6 OUT
OVER-
5 COMP
ORDER
PART NUMBER
LT1115CN8
–
+
N PACKAGE
8-LEAD PDIP
T
JMAX
= 115°C,
θ
JA
= 130°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
THD
IMD
V
OS
I
OS
I
B
e
n
PARAMETER
Total Harmonic Distortion at 10kHz
Inter-Modulation Distortion (CCIF)
Input Offset Voltage
Input Offset Current
Input Bias Current
Input Noise Voltage Density
Wideband Noise
Corresponding Voltage Level
re 0.775V
i
n
Input Noise Current Density
(Note 3)
Input Resistance
Common Mode
Differential Mode
Input Capacitance
Input Voltage Range
CONDITIONS
Av = –10, V
O
= 7V
RMS
, R
L
= 600
Av = 10, V
O
= 7V
RMS
, R
L
= 600
(Note 2)
V
CM
= 0V
V
CM
= 0V
fo = 10Hz
fo = 1000Hz, 100% tested
DC to 20kHz
fo = 10Hz
fo = 1000Hz, 100% tested
2
U
U
W W
W
TOP VIEW
NC 1
NC 2
TRIM 3
–IN 4
+IN 5
V
–
6
NC 7
NC 8
–
+
16 NC
15 NC
14 TRIM
13 V
+
12 OUTPUT
11 OVERCOMP
10 NC
9
NC
ORDER
PART NUMBER
LT1115CSW
SW PACKAGE
16-LEAD PLASTIC SO
T
MAX
= 115°C,
θ
JA
= 130°C/W
LT1115 • POI01
V
S
=
±18V,
T
A
= 25°C, unless otherwise noted.
MIN
TYP
< 0.002
< 0.0002
50
30
±50
1.0
0.9
120
– 136
4.7
1.2
250
15
5
±13.5
±15.0
200
200
±380
1.2
MAX
UNITS
%
%
µV
nA
nA
nV/√Hz
nV/√Hz
nV
RMS
dB
pA/√Hz
pA/√Hz
MΩ
kΩ
pF
V
2.2
1115fa
LT1115
ELECTRICAL CHARACTERISTICS
SYMBOL
CMRR
PSRR
A
VOL
PARAMETER
Common Mode Rejection
Ratio
Power Supply Rejection
Ratio
Large-Signal Voltage Gain
V
S
=
±18V,
T
A
= 25°C, unless otherwise noted.
MIN
104
104
2.0
1.5
1.0
±15.5
±14.5
±11.0
10
40
TYP
123
126
20
15
10
±16.5
±15.5
±14.5
15
70
70
8.5
11.5
MAX
UNITS
dB
dB
V/µV
V/µV
V/µV
V
V
V
V/µs
MHz
Ω
mA
CONDITIONS
V
CM
=
±13.5V
V
S
=
±4V
to
±19V
R
L
≥
2kΩ, Vo =
±14.5V
R
L
≥
1kΩ, Vo =
±13V
R
L
≥
600Ω, Vo =
±10V
No Load
R
L
≥
2kΩ
R
L
≥
600Ω
A
VCL
= –1
fo = 20kHz (Note 4)
Vo = 0, Io = 0
V
OUT
Maximum Output Voltage
Swing
Slew Rate
Gain-Bandwidth Product
Open Loop 0utput Impedance
Supply Current
SR
GBW
Zo
I
S
The
●
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
V
S
=
±18V,
unless otherwise noted.
SYMBOL
V
OS
∆V
OS
/∆T
I
OS
I
B
CMRR
PSRR
A
VOL
V
OUT
PARAMETER
Input Offset Voltage
Average Input Offset Drift
Input Offset Current
Input Bias Current
Input Voltage Range
Common Mode Rejection
Ratio
Power Supply Rejection
Ratio
Large-Signal Voltage Gain
Maximum Output Voltage
Swing
Supply Current
V
CM
=
±13V
V
S
=
±4.5V
to
±18V
R
L
≥
2kΩ, Vo =
±13V
R
L
≥
1kΩ, Vo =
±11V
No Load
R
L
≥
2kΩ
R
L
≥
600Ω
V
CM
= 0V
V
CM
= 0V
●
●
●
●
●
●
CONDITIONS
(Note 2)
●
MIN
TYP
75
0.5
40
±70
MAX
280
300
±550
UNITS
µV
µV/°C
nA
nA
V
dB
dB
V/µV
V/µV
V
V
V
±13
100
100
1.5
1.0
±15
±13.8
±10
±14.8
120
123
15
10
±16.3
±15.3
±14.3
9.3
13
●
●
I
S
mA
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Input Offset Voltage measurements are performed by automatic
test equipment approximately 0.5 sec after application of power.
Note 3:
Current noise is defined and measured with balanced source
resistors. The resultant voltage noise (after subtracting the resistor noise
on an RMS basis) is divided by the sum of the two source resistors to
obtain current noise.
Note 4:
Gain-bandwidth product is not tested. It is guaranteed by design
and by inference from the slew rate measurement.
Note 5:
The inputs are protected by back-to-back diodes. Current limiting
resistors are not used in order to achieve low noise. If differential input
voltage exceeds
±1.8V,
the input current should be limited to 25mA.
1115fa
3
LT1115
TYPICAL PERFOR A CE CHARACTERISTICS
Wideband Noise, DC to 20kHz
10
V
S
=
±
18V
T
A
= 25
°
C
TOTAL NOISE DENSITY (nV/√Hz)
RMS VOLTAGE NOISE (µV)
0.5µV/DIV
FPO
0.5ms/DIV
0.01
100
1k
100k
10k
BANDWIDTH (Hz)
1M
10M
0.1
1
THD + Noise vs Frequency
(A
V
= –10)
TOTAL HARMONIC DISTORTION + NOISE (%)
TOTAL HARMONIC DISTORTION + NOISE (%)
TOTAL HARMONIC DISTORTION + NOISE (%)
0.010
A
V
= – 10
R
L
= 600
V
IN
= 2V
P-P
(700mV
RMS)
V
OUT
= 20V
P-P
(7V
RMS)
T
A
= 25
°
C
V
S
=
±18V
0.001
0.0005
20
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC04
THD + Noise vs Frequency
(A
V
= 10)
TOTAL HARMONIC DISTORTION + NOISE (%)
TOTAL HARMONIC DISTORTION + NOISE (%)
A
V
= 10
R
L
= 600
V
IN
= 2V
P-P
(700mV
RMS)
V
OUT
= 20V
P-P
(7V
RMS)
T
A
= 25
°
C
V
S
=
±18V
A
V
= 100
V
IN
= 200mV
P-P
(700V
RMS)
V
OUT
= 20mV
P-P
(7V
RMS)
T
A
= 25
°
C
R
L
= 600
V
S
=
±18V
0.010
TOTAL HARMONIC DISTORTION + NOISE (%)
0.010
0.001
0.0005
20
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC07
4
U W
Wideband Voltage Noise
(0.1Hz to Frequency Indicated)
100
Total Noise vs Matched Source
Resistance
R
S
–
R
S
+
1
10
AT 10Hz
1.0
AT 1kHz
2 R
S
NOISE ONLY
0.1
V
S
=
±
18V
T
A
= 25
°
C
3
10 30 100 300 1k 3k 10k
MATCHED SOURCE RESISTANCE, R
S
(Ω)
LT1115 • TPC03
LT1115 • TPC02
THD + Noise vs Frequency
(A
V
= –100)
0.1
A
V
= –100
R
L
= 600
V
IN
= 200mV
P-P
(70mV
RMS)
V
OUT
= 20V
P-P
(7V
RMS)
T
A
= 25
°
C
V
S
=
±18V
0.010
0.1
THD + Noise vs Frequency
(A
V
= –1000)
AV = – 1000
R
L
= 600
V
IN
= 20mV
P-P
(7mV
RMS)
V
OUT
= 20V
P-P
(7V
RMS)
T
A
= 25
°
C
V
S
=
±18V
0.010
0.001
20
0.001
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC05
20
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC06
THD + Noise vs Frequency
(A
V
= 100)
0.1
0.1
THD + Noise vs Frequency
(A
V
= 1000)
A
V
= 1000
V
IN
= 20mV
P-P
(7mV
RMS)
V
OUT
= 20V
P-P
(7V
RMS)
T
A
= 25
°
C
R
L
= 600
V
S
=
±18V
0.010
0.001
0.0005
20
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC08
0.001
20
100
1k
FREQUENCY (Hz)
20k
LT1115 • TPC09
1115fa
LT1115
TYPICAL PERFOR A CE CHARACTERISTICS
CCIF IMD Test (Twin Equal
Amplitude Tones at 13 and 14kHz)*
INTERMODULATION DISTORTION (at 1kHz) (%)
INTERMODULATION DISTORTION (at 1kHz) (%)
0.1
A
V
= 10
R
L
= 600
T
A
= 25
°
C
V
S
=
±18V
0.010
SLEW RATE (V/µs)
0.001
0.0001
10m
0.1
1
OUTPUT AMPLITUDE (V
RMS
)
Total Noise vs Unmatched Source
Resistance
100
R
S
CURRENT NOISE DENSITY (pA/√Hz)
TOTAL NOISE DENSITY (nV/√Hz)
100
RMS VOLTAGE NOISE DENSITY (nV/√Hz)
10
AT 10Hz
1.0
AT 1kHz
R
S
NOISE ONLY
V
S
=
±
18V
T
A
= 25
°
C
0.1
1
3
10 30 100 300 1k 3k 10k
UNMATCHED SOURCE RESISTANCE, R
S
(Ω)
LT1115 • TPC13
Voltage Noise vs Supply Voltage
1.5
10
RMS VOLTAGE NOISE DENSITY (nV/√Hz)
T
A
= 25°C
1.25
SUPPLY CURRENT (mA)
8
7
6
5
4
3
2
1
V
S
=
±15V
V
S
=
±
5V
SHORT-CIRCUIT CURRENT (mA)
SINKING
SOURCING
1.0
AT 1kHz
0.75
0.5
0
±
5
±
10
±
15
SUPPLY VOLTAGE (V)
±20
LT1115 • TPC16
*See CCIF Test Note at end of “Typical Performance Characteristics”.
1115fa
U W
10
LT1115 • TPC10
CCIF IMD Test (Twin Equal
Amplitude Tones at 13 and 14kHz)*
0.1
A
V
= 10
R
L
= 10k
T
A
= 25
°
C
V
S
=
±18V
0.010
Slew Rate, Gain-Bandwidth-Product
vs Overcompensation Capacitor
100
10000
10
GWB
1000
GAIN AT 20kHz
SLEW
1
C
OC
FROM PIN 5 TO PIN 6
V
S
=
±18V
T
A
= 25
°
C
1
100
0.001
0.0001
10m
0.1
1
0.1
OUTPUT AMPLITUDE (V
RMS
)
10
10
10000
1000
10
100
OVERCOMPENSATION CAPACITOR (pF)
LT1115 • TPC12
LT1115 • TPC11
Current Noise Spectrum
2.0
Voltage Noise vs Temperature
V
S
=
±18V
1.6
10
1.2
AT 10Hz
AT 1kHz
TYPICAL
1
1/f CORNER = 250Hz
0.8
0.4
0.1
10
0
1k
100
FREQUENCY (Hz)
10k
LT1115 • TPC14
0
15
30
45
TEMPERATURE (°C)
60
75
LT1115 • TPC15
Supply Current vs Temperature
50
V
S
=
±18V
9
Output Short-Circuit Current
vs Time
40
30
20
10
0
– 10
– 20
– 30
– 40
25°C
V
S
=
±
18V
25°C
0
0
15
30
45
TEMPERATURE (°C)
60
75
LT1115 • TPC17
– 50
2
3
0
1
TIME FROM OUTPUT SHORT TO GROUND (MINUTES)
LT1115 • TPC18
5
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