LT1028/LT1128
Ultra Low Noise Precision
High Speed Op Amps
FEATURES
s
DESCRIPTIO
s
s
s
s
s
s
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
Voltage and Current Noise 100% Tested
Gain-Bandwidth Product
LT1028: 50MHz Min.
LT1128: 13MHz Min.
Slew Rate
LT1028: 11V/µs Min.
LT1128: 5V/µs Min.
Offset Voltage: 40µV Max.
Drift with Temperature: 0.8µV/°C Max.
Voltage Gain: 7 Million Min.
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 (0.1µV/°C drift, 10µV 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 50Ω 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.
APPLICATI
s
s
s
s
s
s
s
S
Low Noise Frequency Synthesizers
High Quality Audio
Infrared Detectors
Accelerometer and Gyro Amplifiers
350Ω Bridge Signal Conditioning
Magnetic Search Coil Amplifiers
Hydrophone Amplfiers
Flux Gate Amplifier
10
VOLTAGE NOISE DENSITY (nV/√Hz)
DEMODULATOR
SYNC
OUTPUT TO
DEMODULATOR
1k
+
LT1028
–
SQUARE
WAVE
DRIVE
1kHz
FLUX GATE
TYPICAL
SCHONSTEDT
#203132
1
1/f CORNER = 3.5Hz
50Ω
0.1
0.1
1028/1128 TA01
U
Voltage Noise vs Frequency
V
S
= ±15V
T
A
= 25°C
MAXIMUM
1/f CORNER = 14Hz
TYPICAL
1
10
100
FREQUENCY (Hz)
1k
1028/1128 TA02
UO
1
LT1028/LT1128
ABSOLUTE
AXI U
RATI GS
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
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
PACKAGE/ORDER I FOR ATIO
TOP VIEW
V
OS
TRIM
8
V
OS
TRIM 1
–
ORDER PART
NUMBER
7 V
+
6 OUT
5 OVER-
COMP
–IN 2
+
+IN 3
4
V
–
(CASE)
LT1028AMH
LT1028MH
LT1028ACH
LT1028CH
H PACKAGE
8-LEAD TO-5 METAL CAN
TOP VIEW
V
OS
TRIM 1
–IN 2
+IN 3
V
–
8
–
+
V
OS
TRIM
7 V+
OUT
6
4
5 OVER-
COMP
J8 PACKAGE
8-LEAD CERAMIC DIP
N8 PACKAGE
8-LEAD PLASTIC DIP
LT1028AMJ8
LT1028MJ8
LT1028ACJ8
LT1028CJ8
LT1028ACN8
LT1028CN8
LT1128AMJ8
LT1128MJ8
LT1128CJ8
LT1128ACN8
LT1128CN8
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
∆V
OS
∆Time
I
OS
I
B
e
n
PARAMETER
Input Offset Voltage
Long Term Input Offset
Voltage Stability
Input Offset Current
Input Bias Current
Input Noise Voltage
CONDITIONS
(Note 1)
(Note 2)
V
S
=
±15V,
T
A
= 25°C, unless otherwise noted.
LT1028AM/AC
LT1128AM/AC
MIN
TYP
10
0.3
12
±25
35
MAX
40
V
CM
= 0V
V
CM
= 0V
0.1Hz to 10Hz (Note 3)
2
U
U
W
W W
U
W
TOP VIEW
V
OS
TRIM 1
–IN 2
+IN 3
V
–
ORDER PART
NUMBER
8
7
6
5
V
OS
TRIM
V+
OUT
OVER-
COMP
–
+
LT1028CS8
LT1128CS8
S8 PART MARKING
1028
1128
ORDER PART
NUMBER
LT1028CS16
4
S8 PACKAGE
8-LEAD PLASTIC SOIC
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 OUT
11 OVER-
COMP
10 NC
9
NC
S PACKAGE
16-LEAD PLASTIC SOL
NOTE:
THIS DEVICE IS NOT RECOM-
MENDED FOR NEW DESIGNS
LT1028M/C
LT1128M/C
MIN
TYP
20
0.3
18
±30
35
MAX
80
UNITS
µV
µV/Mo
nA
nA
nV
P-P
50
±90
75
100
±180
90
LT1028/LT1128
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Input Noise Voltage Density
I
n
Input Noise Current Density
Input Resistance
Common Mode
Differential Mode
Input Capacitance
Input Voltage Range
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Large-Signal Voltage Gain
V
S
=
±15V,
T
A
= 25°C, unless otherwise noted.
LT1028AM/AC
LT1128AM/AC
LT1028M/C
LT1128M/C
MIN
TYP
1.0
0.9
4.7
1.0
300
20
5
±12.2
126
132
30.0
20.0
15.0
±13.0
±12.2
15.0
6.0
75
20
80
7.6
MAX
1.9
1.2
12.0
1.8
UNITS
nV/√Hz
nV/√Hz
pA/√Hz
pA/√Hz
MΩ
kΩ
pF
V
dB
dB
V/µV
V/µV
V/µV
V
V
V/µs
V/µs
MHz
MHz
Ω
mA
CONDITIONS
f
O
= 10Hz (Note 4)
f
O
= 1000Hz, 100% tested
f
O
= 10Hz (Note 3 and 5)
f
O
= 1000Hz, 100% tested
MIN
TYP
1.00
0.85
4.7
1.0
MAX
1.7
1.1
10.0
1.6
CMRR
PSRR
A
VOL
V
OUT
SR
GBW
Z
O
I
S
Maximum Output Voltage Swing
Slew Rate
Gain-Bandwidth Product
Open-Loop Output Impedance
Supply Current
V
CM
=
±11V
V
S
=
±4V
to
±18V
R
L
≥
2k, V
O
=
±12V
R
L
≥
1k, V
O
=
±10V
R
L
≥
600Ω, V
O
=
±10V
R
L
≥
2k
R
L
≥
600Ω
A
VCL
= –1
A
VCL
= –1
f
O
= 20kHz (Note 6)
f
O
= 200kHz (Note 6)
V
O
= 0, I
O
= 0
LT1028
LT1128
LT1028
LT1128
300
20
5
±11.0 ±12.2
114
126
117
133
7.0
30.0
5.0
20.0
3.0
15.0
±12.3 ±13.0
±11.0 ±12.2
11.0 15.0
5.0
6.0
50
75
13
20
80
7.4
±11.0
110
110
5.0
3.5
2.0
±12.0
±10.5
11.0
4.5
50
11
9.5
10.5
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
∆V
OS
∆Temp
I
OS
I
B
CMRR
PSRR
A
VOL
V
OUT
I
S
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
CONDITIONS
(Note 1)
(Note7)
V
CM
= 0V
V
CM
= 0V
V
S
=
±15V,
–55°C
≤
T
A
≤
125°C, unless otherwise noted.
LT1028AM
LT1128AM
MIN
q
q
q
q
q
q
q
q
q
q
LT1028M
LT1128M
MAX
120
0.8
MIN
TYP
45
0.25
30
±50
±11.7
120
130
14.0
10.0
±11.6
9.0
MAX
180
1.0
180
±300
UNITS
µV
µV/°C
nA
nA
V
dB
dB
V/µV
V/µV
V
mA
TYP
30
0.2
V
CM
=
±10.3V
V
S
=
±4.5V
to
±16V
R
L
≥
2k, V
O
=
±10V
R
L
≥
1k, V
O
=
±10V
R
L
≥
2k
25
±40
±10.3 ±11.7
106
122
110
130
3.0
14.0
2.0
10.0
±10.3 ±11.6
8.7
90
±150
±10.3
100
104
2.0
1.5
±10.3
11.5
13.0
3
LT1028/LT1128
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
∆V
OS
∆Temp
I
OS
I
B
CMRR
PSRR
A
VOL
V
OUT
I
S
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
CONDITIONS
(Note 1)
(Note7)
V
CM
= 0V
V
CM
= 0V
V
S
=
±15V,
0°C
≤
T
A
≤
70°C, unless otherwise noted.
LT1028AC
LT1128AC
MIN
q
q
q
q
q
q
q
q
q
q
LT1028C
LT1128C
MAX
80
0.8
65
±120
±10.5
106
107
3.0
2.5
±11.5
±9.0
10.5
MIN
TYP
30
0.2
22
±40
±12.0
124
132
25.0
18.0
±12.7
±10.5
8.2
MAX
125
1.0
130
±240
UNITS
µV
µV/°C
nA
nA
V
dB
dB
V/µV
V/µV
V
V
mA
TYP
15
0.1
V
CM
=
±10.5V
V
S
=
±4.5V
to
±18V
R
L
≥
2k, V
O
=
±10V
R
L
≥
1k, V
O
=
±10V
R
L
≥
2k
R
L
≥
600Ω (Note 9)
15
±30
±10.5 ±12.0
110
124
114
132
5.0
25.0
4.0
18.0
±11.5 ±12.7
±9.5 ±11.0
8.0
11.5
ELECTRICAL CHARACTERISTICS
SYMBOL
V
OS
∆V
OS
∆Temp
I
OS
I
B
CMRR
PSRR
A
VOL
V
OUT
I
S
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
CONDITIONS
V
S
=
±15V,
– 40°C
≤
T
A
≤
85°C, unless otherwise noted. (Note 10)
LT1028AC
LT1128AC
MIN
q
q
LT1028C
LT1128C
MAX
95
0.8
80
±140
±10.4
102
106
2.5
2.0
±11.0
11.0
MIN
TYP
35
0.25
28
±45
±11.8
123
131
20.0
14.0
±12.5
8.7
MAX
150
1.0
160
±280
UNITS
µV
µV/°C
nA
nA
V
dB
dB
V/µV
V/µV
V
mA
TYP
20
0.2
V
CM
= 0V
V
CM
= 0V
V
CM
=
±10.5V
V
S
=
±4.5V
to
±18V
R
L
≥
2k, V
O
=
±10V
R
L
≥
1k, V
O
=
±10V
R
L
≥
2k
q
q
q
q
q
q
q
q
20
±35
±10.4 ±11.8
108
123
112
131
4.0
20.0
3.0
14.0
±11.0 ±12.5
8.5
12.5
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 2.5µV.
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
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.
4
LT1028/LT1128
TYPICAL PERFOR A CE CHARACTERISTICS
10Hz Voltage Noise Distribution
180
160
140
158
148
120
100
80
60
40
20
0
0.6
8
70
57
RMS VOLTAGE NOISE (µV)
NUMBER OF UNITS
V
S
= ±15V
T
A
= 25°C
500 UNITS
MEASURED
FROM 4 RUNS
28
74 3
2 2 2 12
3 21 1
1
0.8 1.0 1.2 1.4 1.6 1.8 2.0
VOLTAGE NOISE DENSITY (nV/√Hz)
LT1020/1120 • TPC01
Total Noise vs Matched Source
Resistance
100
R
S
TOTAL NOISE DENSITY (nV/√Hz)
R
S
+
TOTAL NOISE DENSITY (nV/√Hz)
–
CURRENT NOISE DENSITY (pA/√Hz)
10
AT 10Hz
1
2 R
S
NOISE ONLY
V
S
= ±15V
T
A
= 25°C
0.1
1
3
10 30 100 300 1k 3k
MATCHED SOURCE RESISTANCE (Ω)
10k
AT 1kHz
LT1028/1128 • TPC04
0.1Hz to 10Hz Voltage Noise
V
S
= ±15V
T
A
= 25°C
RMS VOLTAGE DENSITY (nV/√Hz)
10nV
0
2
6
4
TIME (SEC)
LT1028/1128 • TPC07
U W
2.2
8
10
Wideband Noise, DC to 20kHz
10
Wideband Voltage Noise
(0.1Hz to Frequency Indicated)
V
S
= ±15V
T
A
= 25°C
1
0.1
VERTICAL SCALE = 0.5µV/DIV
HORIZONTAL SCALE = 0.5ms/DIV
0.01
100
1k
10k
100k
BANDWIDTH (Hz)
1M
10M
LT1028/1128 • TPC03
Total Noise vs Unmatched
Source Resistance
100
R
S
Current Noise Spectrum
100
10
10
MAXIMUM
1/f CORNER = 800Hz
TYPICAL
AT 10Hz
1
AT 1kHz
1
1/f CORNER = 250Hz
2 R
S
NOISE ONLY
V
S
= ±15V
T
A
= 25°C
0.1
1
3
10 30 100 300 1k 3k 10k
UNMATCHED SOURCE RESISTANCE (Ω)
LT1028/1128 • TPC05
0.1
10
100
1k
FREQUENCY (Hz)
10k
LT1028/1128 • TPC06
0.01Hz to 1Hz Voltage Noise
2.0
V
S
= ±15V
T
A
= 25°C
Voltage Noise vs Temperature
V
S
= ±15V
1.6
1.2
AT 10Hz
0.8
AT 1kHz
10nV
O.4
0
20
60
40
TIME (SEC)
80
100
0
–50 –25
50
25
0
75
TEMPERATURE (°C)
100
125
LT1028/1128 • TPC07
LT1028/1128 • TPC09
5
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