1
LT1028/LT1128
s
Voltage Noise
1.1nV/
Hz Max. at 1kHz
0.85nV/
Hz Typ. at 1kHz
1.0nV/
Hz Typ. at 10Hz
35nV
P-P
Typ., 0.1Hz to 10Hz
s
Voltage and Current Noise 100% Tested
s
Gain-Bandwidth Product
LT1028: 50MHz Min.
LT1128: 13MHz Min.
s
Slew Rate
LT1028: 11V/
s Min.
LT1128: 5V/
s Min.
s
Offset Voltage: 40
V Max.
s
Drift with Temperature: 0.8
V/
C Max.
s
Voltage Gain: 7 Million Min.
s
Available in 8-Pin SO Package
The LT1028(gain of 1 stable)/LT1128(gain of +1 stable)
achieve a new standard of excellence in noise performance
with 0.85nV/
Hz 1kHz noise, 1.0nV/
Hz 10Hz noise. This
ultra low noise is combined with excellent high speed
specifications (gain-bandwidth product is 75MHz for
LT1028, 20MHz for LT1128), distortion-free output, and
true precision parameters (0.1
V/
C drift, 10
V offset
voltage, 30 million voltage gain). Although the LT1028/
LT1128 input stage operates at nearly 1mA of collector
current to achieve low voltage noise, input bias current is
only 25nA.
The LT1028/LT1128's voltage noise is less than the noise
of a 50
resistor. Therefore, even in very low source
impedance transducer or audio amplifier applications, the
LT1028/LT1128's contribution to total system noise will
be negligible.
Ultra Low Noise Precision
High Speed Op Amps
U
S
A
O
PPLICATI
Flux Gate Amplifier
Voltage Noise vs Frequency
+
DEMODULATOR
SYNC
OUTPUT TO
DEMODULATOR
LT1028
1k
50
SQUARE
WAVE
DRIVE
1kHz
FLUX GATE
TYPICAL
SCHONSTEDT
#203132
1028/1128 TA01
FREQUENCY (Hz)
1
0.1
1
10
10
100
1028/1128 TA02
VOLTAGE NOISE DENSITY (nV/
Hz)
0.1
1k
1/f CORNER = 3.5Hz
1/f CORNER = 14Hz
TYPICAL
MAXIMUM
V
S
= 15V
T
A
= 25C
S
FEATURE
s
Low Noise Frequency Synthesizers
s
High Quality Audio
s
Infrared Detectors
s
Accelerometer and Gyro Amplifiers
s
350
Bridge Signal Conditioning
s
Magnetic Search Coil Amplifiers
s
Hydrophone Amplfiers
D
U
ESCRIPTIO
2
LT1028/LT1128
Supply Voltage
55
C to 105
C ................................................
22V
105
C to 125
C ................................................
16V
Differential Input Current (Note 8) ......................
25mA
Input Voltage ............................ Equal to Supply Voltage
Output Short Circuit Duration .......................... Indefinite
A
U
G
W
A
W
U
W
A
R
BSOLUTE
XI
TI
S
Operating Temperature Range
LT1028/LT1128AM, M ..................... 55
C to 125
C
LT1028/LT1128AC, C ......................... 40
C to 85
C
Storage Temperature Range
All Devices ........................................ 65
C to 150
C
Lead Temperature (Soldering, 10 sec.) ................. 300
C
W
U
U
PACKAGE/ORDER I FOR ATIO
S8 PART MARKING
LT1028CS8
LT1128CS8
ORDER PART
NUMBER
ORDER PART
NUMBER
ORDER PART
NUMBER
1
2
3
4
5
6
7
8
TOP VIEW
IN
+IN
V
S8 PACKAGE
8-LEAD PLASTIC SOIC
V+
OUT
+
V
OS
TRIM
V
OS
TRIM
OVER-
COMP
1028
1128
LT1028AMH
LT1028MH
LT1028ACH
LT1028CH
LT1028AMJ8
LT1028MJ8
LT1028ACJ8
LT1028CJ8
LT1028ACN8
LT1028CN8
LT1128AMJ8
LT1128MJ8
LT1128CJ8
LT1128ACN8
LT1128CN8
LT1028CS16
TOP VIEW
V
+
V
OS
TRIM
IN
OUT
OVER-
COMP
+IN
V
(CASE)
8
7
5
3
2
1
4
H PACKAGE
8-LEAD TO-5 METAL CAN
V
OS
TRIM
+
6
N8 PACKAGE
8-LEAD PLASTIC DIP
1
2
3
4
5
6
7
8
TOP VIEW
IN
+IN
V
V+
OUT
+
J8 PACKAGE
8-LEAD CERAMIC DIP
OVER-
COMP
V
OS
TRIM
V
OS
TRIM
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 1)
10
40
20
80
V
V
OS
Long Term Input Offset
(Note 2)
0.3
0.3
V/Mo
Time
Voltage Stability
I
OS
Input Offset Current
V
CM
= 0V
12
50
18
100
nA
I
B
Input Bias Current
V
CM
= 0V
25
90
30
180
nA
e
n
Input Noise Voltage
0.1Hz to 10Hz (Note 3)
35
75
35
90
nV
P-P
ELECTRICAL C
C
HARA TERISTICS
V
S
=
15V, T
A
= 25
C, unless otherwise noted.
LT1028AM/AC
LT1128AM/AC
LT1028M/C
LT1128M/C
TOP VIEW
S PACKAGE
16-LEAD PLASTIC SOL
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
NC
NC
TRIM
IN
+IN
V
NC
NC
NC
NC
TRIM
V
+
OUT
NC
NC
NOTE: THIS DEVICE IS NOT RECOM-
MENDED FOR NEW DESIGNS
OVER-
COMP
+
3
LT1028/LT1128
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Input Noise Voltage Density
f
O
= 10Hz (Note 4)
1.00
1.7
1.0
1.9
nV/
Hz
f
O
= 1000Hz, 100% tested
0.85
1.1
0.9
1.2
nV/
Hz
I
n
Input Noise Current Density
f
O
= 10Hz (Note 3 and 5)
4.7
10.0
4.7
12.0
pA/
Hz
f
O
= 1000Hz, 100% tested
1.0
1.6
1.0
1.8
pA/
Hz
Input Resistance
Common Mode
300
300
M
Differential Mode
20
20
k
Input Capacitance
5
5
pF
Input Voltage Range
11.0
12.2
11.0
12.2
V
CMRR
Common-Mode Rejection Ratio
V
CM
=
11V
114
126
110
126
dB
PSRR
Power Supply Rejection Ratio
V
S
=
4V to
18V
117
133
110
132
dB
A
VOL
Large-Signal Voltage Gain
R
L
2k, V
O
=
12V
7.0
30.0
5.0
30.0
V/
V
R
L
1k, V
O
=
10V
5.0
20.0
3.5
20.0
V/
V
R
L
600
, V
O
=
10V
3.0
15.0
2.0
15.0
V/
V
V
OUT
Maximum Output Voltage Swing
R
L
2k
12.3
13.0
12.0
13.0
V
R
L
600
11.0
12.2
10.5
12.2
V
SR
Slew Rate
A
VCL
= 1
LT1028
11.0
15.0
11.0
15.0
V/
s
A
VCL
= 1
LT1128
5.0
6.0
4.5
6.0
V/
s
GBW
Gain-Bandwidth Product
f
O
= 20kHz (Note 6)
LT1028
50
75
50
75
MHz
f
O
= 200kHz (Note 6)
LT1128
13
20
11
20
MHz
Z
O
Open-Loop Output Impedance
V
O
= 0, I
O
= 0
80
80
I
S
Supply Current
7.4
9.5
7.6
10.5
mA
ELECTRICAL C
C
HARA TERISTICS
V
S
=
15V, T
A
= 25
C, unless otherwise noted.
LT1028AM/AC
LT1128AM/AC
LT1028M/C
LT1128M/C
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 1)
q
30
120
45
180
V
V
OS
Average Input Offset Drift
(Note7)
q
0.2
0.8
0.25
1.0
V/
C
Temp
I
OS
Input Offset Current
V
CM
= 0V
q
25
90
30
180
nA
I
B
Input Bias Current
V
CM
= 0V
q
40
150
50
300
nA
Input Voltage Range
q
10.3
11.7
10.3
11.7
V
CMRR
Common-Mode Rejection Ratio
V
CM
=
10.3V
q
106
122
100
120
dB
PSRR
Power Supply Rejection Ratio
V
S
=
4.5V to
16V
q
110
130
104
130
dB
A
VOL
Large-Signal Voltage Gain
R
L
2k, V
O
=
10V
q
3.0
14.0
2.0
14.0
V/
V
R
L
1k, V
O
=
10V
2.0
10.0
1.5
10.0
V/
V
V
OUT
Maximum Output Voltage Swing
R
L
2k
q
10.3
11.6
10.3
11.6
V
I
S
Supply Current
q
8.7
11.5
9.0
13.0
mA
LT1028AM
LT1128AM
LT1028M
LT1128M
ELECTRICAL C
C
HARA TERISTICS
V
S
=
15V, 55
C
T
A
125
C, unless otherwise noted.
4
LT1028/LT1128
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
(Note 1)
q
15
80
30
125
V
V
OS
Average Input Offset Drift
(Note7)
q
0.1
0.8
0.2
1.0
V/
C
Temp
I
OS
Input Offset Current
V
CM
= 0V
q
15
65
22
130
nA
I
B
Input Bias Current
V
CM
= 0V
q
30
120
40
240
nA
Input Voltage Range
q
10.5
12.0
10.5
12.0
V
CMRR
Common-Mode Rejection Ratio
V
CM
=
10.5V
q
110
124
106
124
dB
PSRR
Power Supply Rejection Ratio
V
S
=
4.5V to
18V
q
114
132
107
132
dB
A
VOL
Large-Signal Voltage Gain
R
L
2k, V
O
=
10V
q
5.0
25.0
3.0
25.0
V/
V
R
L
1k, V
O
=
10V
4.0
18.0
2.5
18.0
V/
V
V
OUT
Maximum Output Voltage Swing
R
L
2k
q
11.5
12.7
11.5
12.7
V
R
L
600
(Note 9)
9.5
11.0
9.0
10.5
V
I
S
Supply Current
q
8.0
10.5
8.2
11.5
mA
V
S
=
15V, 0
C
T
A
70
C, unless otherwise noted.
LT1028AC
LT1128AC
LT1028C
LT1128C
ELECTRICAL C
C
HARA TERISTICS
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
V
OS
Input Offset Voltage
q
20
95
35
150
V
V
OS
Average Input Offset Drift
q
0.2
0.8
0.25
1.0
V/
C
Temp
I
OS
Input Offset Current
V
CM
= 0V
q
20
80
28
160
nA
I
B
Input Bias Current
V
CM
= 0V
q
35
140
45
280
nA
Input Voltage Range
q
10.4
11.8
10.4
11.8
V
CMRR
Common-Mode Rejection Ratio
V
CM
=
10.5V
q
108
123
102
123
dB
PSRR
Power Supply Rejection Ratio
V
S
=
4.5V to
18V
q
112
131
106
131
dB
A
VOL
Large-Signal Voltage Gain
R
L
2k, V
O
=
10V
q
4.0
20.0
2.5
20.0
V/
V
R
L
1k, V
O
=
10V
3.0
14.0
2.0
14.0
V/
V
V
OUT
Maximum Output Voltage Swing
R
L
2k
q
11.0
12.5
11.0
12.5
V
I
S
Supply Current
q
8.5
11.0
8.7
12.5
mA
V
S
=
15V, 40
C
T
A
85
C, unless otherwise noted. (Note 10)
LT1028AC
LT1128AC
LT1028C
LT1128C
ELECTRICAL C
C
HARA TERISTICS
on an RMS basis) is divided by the sum of the two source resistors to
obtain current noise. Maximum 10Hz current noise can be inferred from
100% testing at 1kHz.
Note 6: Gain-bandwidth product is not tested. It is guaranteed by design
and by inference from the slew rate measurement.
Note 7: This parameter is not 100% tested.
Note 8: 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.
Note 9: This parameter guaranteed by design, fully warmed up at T
A
=
70
C. It includes chip temperature increase due to supply and load
currents.
Note 10: The LT1028/LT1128 are not tested and are not quality-
assurance-sampled at 40
C and at 85
C. These specifications are
guaranteed by design, correlation and/or inference from 55
C, 0
C, 25
C,
70
C and /or 125
C tests.
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1: Input Offset Voltage measurements are performed by automatic
test equipment approximately 0.5 sec. after application of power. In
addition, at T
A
= 25
C, offset voltage is measured with the chip heated to
approximately 55
C to account for the chip temperature rise when the
device is fully warmed up.
Note 2: Long Term Input Offset Voltage Stability refers to the average
trend line of Offset Voltage vs. Time over extended periods after the first
30 days of operation. Excluding the initial hour of operation, changes in
V
OS
during the first 30 days are typically 2.5
V.
Note 3: This parameter is tested on a sample basis only.
Note 4: 10Hz noise voltage density is sample tested on every lot with the
exception of the S8 and S16 packages. Devices 100% tested at 10Hz are
available on request.
Note 5: Current noise is defined and measured with balanced source
resistors. The resultant voltage noise (after subtracting the resistor noise
5
LT1028/LT1128
C
C
HARA TERISTICS
U
W
A
TYPICAL PERFOR
CE
10Hz Voltage Noise Distribution
Total Noise vs Matched Source
Resistance
Total Noise vs Unmatched
Source Resistance
Current Noise Spectrum
0.01Hz to 1Hz Voltage Noise
TEMPERATURE (C)
50
0
RMS VOLTAGE DENSITY (nV/
Hz)
0.8
2.0
0
50
75
LT1028/1128 TPC09
O.4
1.6
1.2
25
25
100
125
V
S
= 15V
AT 10Hz
AT 1kHz
Voltage Noise vs Temperature
0.1Hz to 10Hz Voltage Noise
TIME (SEC)
0
8
LT1028/1128 TPC07
2
4
6
10
10nV
V
S
= 15V
T
A
= 25C
Wideband Noise, DC to 20kHz
BANDWIDTH (Hz)
100
RMS VOLTAGE NOISE (
V)
0.1
1
100k
1M
10M
LT1028/1128 TPC03
0.01
10
10k
1k
V
S
= 15V
T
A
= 25C
Wideband Voltage Noise
(0.1Hz to Frequency Indicated)
MATCHED SOURCE RESISTANCE (
)
1
TOTAL NOISE DENSITY (nV/
Hz)
10
100
3
1k
10k
LT1028/1128 TPC04
1
0.1
V
S
= 15V
T
A
= 25C
10
30
100 300
3k
AT 10Hz
2 R
S
NOISE ONLY
AT 1kHz
+
R
S
R
S
UNMATCHED SOURCE RESISTANCE (
)
1
TOTAL NOISE DENSITY (nV/
Hz)
10
100
3
1k
10k
LT1028/1128 TPC05
1
0.1
V
S
= 15V
T
A
= 25C
10
30
100 300
3k
AT 10Hz
2 R
S
NOISE ONLY
AT 1kHz
R
S
TIME (SEC)
0
80
LT1028/1128 TPC07
20
40
60
100
10nV
V
S
= 15V
T
A
= 25C
FREQUENCY (Hz)
10
0.1
CURRENT NOISE DENSITY (pA/
Hz)
1
10
100
100
1k
10k
LT1028/1128 TPC06
MAXIMUM
TYPICAL
1/f CORNER = 800Hz
1/f CORNER = 250Hz
0.6
0
NUMBER OF UNITS
20
60
80
100
1.0
1.4
1.8
180
LT1020/1120 TPC01
40
0.8
1.2
120
140
160
1.6
2.0
2.2
8
70
148
158
57
28
7 423 2 2 2
1
3 2 1 1 1
V
S
= 15V
T
A
= 25C
500 UNITS
MEASURED
FROM 4 RUNS
VOLTAGE NOISE DENSITY (nV/
Hz)
VERTICAL SCALE = 0.5
V/DIV
HORIZONTAL SCALE = 0.5ms/DIV
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