LT1055/LT1056
1
10556fd
For more information www.linear.com/LT1055
TYPICAL APPLICATION
FEATURES DESCRIPTION
Precision, High Speed,
JFET Input Operational Amplifiers
The LT
®
1055/LT1056 JFET input operational amplifiers
combine precision specifications with high speed per-
formance.
For the first time, 16V/µs slew rate and 6.5MHz gain
bandwidth product are simultaneously achieved with offset
voltage of typically 50µV, 1.2µV/°C drift, bias currents of
40pA at 70°C and 500pA at 125°C.
The 150µV maximum offset voltage specification is the
best available on any JFET input operational amplifier.
The LT1055 and LT1056 are differentiated by their operating
currents. The lower power dissipation LT1055 achieves
lower bias and offset currents and offset voltage. The ad-
ditional power dissipation of the LT1056 permits higher
slew rate, bandwidth and faster settling time with a slight
sacrifice in DC performance.
The voltage-to-frequency converter shown below is one
of the many applications which utilize both the precision
and high speed of the LT1055/LT1056.
For a JFET input op amp with 23V/µs guaranteed slew
rate, refer to the LT1022 data sheet.
APPLICATIONS
n Guaranteed Offset Voltage: 150µV Max
–55°C to 125°C: 500µV Max
n Guaranteed Drift: 4µV/°C Max
n Guaranteed Bias Current
70°C: 150pA Max
125°C: 2.5nA Max
n Guaranteed Slew Rate: 12V/µs Min
n Available in 8-Pin PDIP and SO Packages
n Precision, High Speed Instrumentation
n Logarithmic Amplifiers
n D/A Output Amplifiers
n Photodiode Amplifiers
n Voltage-to-Frequency Converters
n Frequency-to-Voltage Converters
n Fast, Precision Sample-and-Hold
L, LT, LT C , LT M, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Distribution of Input Offset Voltage
(H Package)
1Hz to 10kHz Voltage-to-Frequency Converter
+
–
0V TO 10V
INPUT
10kHz
TRIM
5k
4.7k
15V
2N3906
15V
–15V
LT1055/56 TA01
–15V
= 1N4148
3M
0.001 (POLYSTYRENE)
0.1µF
THE LOW OFFSET VOLTAGE OF LT1056
CONTRIBUTES ONLY 0.1Hz OF ERROR
WHILE ITS HIGH SLEW RATE PERMITS
10kHz OPERATION.
0.1µF 22k
75k
1.5k
LM329
3.3M
7
6
4
3
2
33pF
*1% FILM
OUTPUT
1Hz TO 10kHz
0.005%
LINEARITY
LT1056
INPUT OFFSET VOLTAGE (µV)
0
NUMBER OF UNITS
20
60
80
100
140
–400 0200
LT1055/56 TA02
40
120
400
–200
VS = ±15V
TA = 25°C
634 UNITS TESTED
FROM THREE RUNS
50% TO ±60µV
LT1055/LT1056
2
10556fd
For more information www.linear.com/LT1055
ABSOLUTE MAXIMUM RATINGS
Supply Voltage .......................................................±20V
Differential Input Voltage ........................................±40V
Input Voltage ..........................................................±20V
Output Short-Circuit Duration .......................... Indefinite
Operating Temperature Range
LT1055AM/LT1055M/LT1056AM/
LT1056M (OBSOLETE) ...................... –55°C to 125°C
LT1055AC/LT1055C/LT1056AC/
LT1056C .................................................. 0°C to 70°C
Storage Temperature Range
All Devices ......................................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ...................300°C
(Note 1)
1
2
3
4
8
7
6
5
TOP VIEW
BAL
–IN
+IN
V–
N/C
V+
OUT
BAL
N8 PACKAGE
8-LEAD PDIP
TJMAX = 150°C, θJA = 130°C/W
1
2
3
4
8
7
6
5
TOP VIEW
S8 PACKAGE
8-LEAD PLASTIC SO
BAL
–IN
+IN
V–
N/C
V+
OUT
BAL
TJMAX = 150°C, θJA = 130°C/W
TOP VIEW
NC
BALANCE
OUT
BALANCE
+IN
V–
8
7
6
5
3
2
1
4
H PACKAGE
8-LEAD TO-5 METAL CAN
–IN
V+
TJMAX = 150°C, θJA = 150°C/W, θJC = 45°C/W
OBSOLETE PACKAGE
Consider the N8 for Alternate Source
PIN CONFIGURATION
LT1055/LT1056
3
10556fd
For more information www.linear.com/LT1055
ELECTRICAL CHARACTERISTICS
TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted.
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LT1055CN8#PBF LT1055CN8#TRPBF LT1055CN8 8-Lead PDIP 0°C to 70°C
LT1056CN8#PBF LT1056CN8#TRPBF LT1056CN8 8-Lead PDIP 0°C to 70°C
LT1055S8#PBF LT1055S8#TRPBF 1055 8-Lead Plastic SO 0°C to 70°C
LT1056S8#PBF LT1056S8#TRPBF 1056 8-Lead Plastic SO 0°C to 70°C
OBSOLETE PACKAGE
LT1055ACH#PBF LT1055ACH#TRPBF LT1055ACH 8-Lead TO-5 Metal Can 0°C to 70°C
LT1055CH#PBF LT1055CH#TRPBF LT1055CH 8-Lead TO-5 Metal Can 0°C to 70°C
LT1055AMH#PBF LT1055AMH#TRPBF LT1055AMH 8-Lead TO-5 Metal Can –55°C to 125°C
LT1055MH#PBF LT1055MH#TRPBF LT1055MH 8-Lead TO-5 Metal Can –55°C to 125°C
LT1056ACH#PBF LT1056ACH#TRPBF LT1056ACH 8-Lead TO-5 Metal Can 0°C to 70°C
LT1056CH#PBF LT1056CH#TRPBF LT1056CH 8-Lead TO-5 Metal Can 0°C to 70°C
LT1056AMH#PBF LT1056AMH#TRPBF LT1056AMH 8-Lead TO-5 Metal Can –55°C to 125°C
LT1056MH#PBF LT1056MH#TRPBF LT1056MH 8-Lead TO-5 Metal Can –55°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part markings, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
SYMBOL PARAMETER CONDITIONS
LT1055AM/LT1056AM
LT1055AC/LT1056AC
LT1055M/LT1056M
LT1055CH/LT1056CH
LT1055CN8/LT1056CN8
UNITSMIN TYP MAX MIN TYP MAX
VOS Input Offset Voltage (Note 2) LT1055 H Package
LT1056 H Package
LT1055 N8 Package
LT1056 N8 Package
50
50
150
180
70
70
120
140
400
450
700
800
µV
µV
µV
µV
IOS Input Offset Current Fully Warmed Up 2 10 2 20 pA
IBInput Bias Current Fully Warmed Up
VCM = 10V
±10
30
±50
130
±10
30
±50
150
pA
pA
Input Resistance:Differential
Input Capacitance
Common Mode VCM = –11V to 8V
VCM = 8V to 11V
1012
1012
1011
4
1012
1012
1011
4
Ω
Ω
Ω
pF
enInput Noise Voltage 0.1Hz to 10Hz LT1055
LT1056
1.8
2.5
2.0
2.8
µVP-P
µVP-P
Input Noise Voltage Density fO = 10Hz (Note 3)
fO = 1kHz (Note 4)
28
14
50
20
30
15
60
22
nV/√Hz
nV/√Hz
InInput Noise Current Density fO = 10Hz, 1kHz (Note 5) 1.8 4 1.8 4 fA/√Hz
AVOL Large-Signal Voltage Gain VO = ±10V RL = 2k
RL = 1k
150
130
400
300
120
100
400
300
V/mV
V/mV
Input Voltage Range ±11 ±12 ±11 ±12 V
CMRR Common Mode Rejection Ratio VCM = ±11V 86 100 83 98 dB
PSRR Power Supply Rejection Ratio VS = ±10V to ±18V 90 106 88 104 dB
VOUT Output Voltage Swing RL = 2k ±12 ±13.2 ±12 ±13.2 V
LT1055/LT1056
4
10556fd
For more information www.linear.com/LT1055
ELECTRICAL CHARACTERISTICS
TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted.t
The l denotes the specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C. VS = ±15V, VCM = 0V unless otherwise noted.
The l denotes the specifications which apply over the temperature range –55°C ≤ TA ≤ 125°C. VS = ±15V, VCM = 0V, unless otherwise noted.
SYMBOL PARAMETER CONDITIONS
LT1055AM/LT1056AM
LT1055AC/LT1056AC
LT1055M/LT1056M
LT1055CH/LT1056CH
LT1055CN8/LT1056CN8
UNITSMIN TYP MAX MIN TYP MAX
SR Slew Rate LT1055
LT1056
10
12
13
16
7.5
9.0
12
14
V/µs
V/µs
GBW Gain Bandwidth Product f = 1MHz LT1055
LT1056
5.0
6.5
4.5
5.5
MHz
MHz
ISSupply Current LT1055
LT1056
2.8
5.0
4.0
6.5
2.8
5.0
4.0
7.0
mA
mA
Offset Voltage Adjustment Range RPOT = 100k ±5 ±5 mV
SYMBOL PARAMETER CONDITIONS
LT1055AC
LT1056AC
LT1055CH/LT1056CH
LT1055CN8/LT1056CN8
UNITSMIN TYP MAX MIN TYP MAX
VOS Input Offset Voltage (Note 2) LT1055 H Package
LT1056 H Package
LT1055 N8 Package
LT1056 N8 Package
l
l
l
l
100
100
330
360
140
140
250
280
750
800
1250
1350
µV
µV
µV
µV
Average Temperature
Coefficient of Input Offset
Voltage
H Package (Note 6)
N8 Package (Note 6)
l
l
1.2 4.0 1.6
3.0
8.0
12.0
µV/°C
µV/°C
IOS Input Offset Current Warmed Up LT1055
TA = 70°C LT1056
l
l
10
14
50
70
16
18
80
100
pA
pA
IBInput Bias Current Warmed Up LT1055
TA = 70°C LT1056
l
l
±30
±40
±150
±80
±40
±50
±200
±240
pA
pA
AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k l80 250 60 250 V/mV
CMRR Common Mode Rejection Ratio VCM = ±10.5V l85 100 82 98 dB
PSRR Power Supply Rejection Ratio VS = ±10V to ±18V l89 105 87 103 dB
VOUT Output Voltage Swing RL = 2k l±12 ±13.1 ±12 ±13.1 V
SYMBOL PARAMETER CONDITIONS
LT1055AM
LT1056AM
LT1055M
LT1056M
UNITSMIN TYP MAX MIN TYP MAX
VOS Input Offset Voltage (Note 2) LT1055
LT1056
l
l
180
180
500
550
250
250
1200
1250
µV
µV
Average Temperature
Coefficient of Input Offset
Voltage
(Note 6) l1.3 4.0 1.8 8.0 µV/°C
IOS Input Offset Current Warmed Up LT1055
TA = 125°C LT1056
l
l
0.20
0.25
1.2
1.5
0.25
0.30
1.8
2.4
nA
nA
IBInput Bias Current Warmed Up LT1055
TA = 125°C LT1056
l
l
±0.4
±0.5
±2.5
±3.0
±0.5
±0.6
±4.0
±5.0
nA
nA
AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k l40 120 35 120 V/mV
CMRR Common Mode Rejection Ratio VCM = ±10.5V l85 100 82 98 dB
PSRR Power Supply Rejection Ratio VS = ±10V to ±17V l88 104 86 102 dB
VOUT Output Voltage Swing RL = 2k l±12 ±12.9 ±12 ±12.9 V
LT1055/LT1056
5
10556fd
For more information www.linear.com/LT1055
ELECTRICAL CHARACTERISTICS
TA = 25°C. VS = ±15V, VCM = 0V unless otherwise noted.
The l denotes the specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C. VS = ±15V, VCM = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS
LT1055CS8/LT1056CS8
UNITSMIN TYP MAX
VOS Input Offset Voltage (Note 2) 500 1500 µV
IOS Input Offset Current Fully Warmed Up 5 30 pA
IBInput Bias Current Fully Warmed Up
VCM = 10V
±30
30
±100
150
pA
pA
Input Resistance Differential
Common Mode
VCM = –11V to 8V
VCM = 8V to 11V
0.4
0.4
0.05
TΩ
TΩ
TΩ
Input Capacitance 4 pF
enInput Noise Voltage 0.1Hz to 10Hz LT1055
LT1056
2.5
3.5
µVP-P
µVP-P
Input Noise Voltage Density fO = 10Hz (Note 4)
fO = 1kHz (Note 4)
35
15
70
22
nV/√Hz
nV/√Hz
inInput Noise Current Density fO = 10Hz, 1kHz (Note 5) 2.5 10 fA/√Hz
AVOL Large-Signal Voltage Gain VO = ±10V RL = 2k
RL = 1k
120
100
400
300
V/mV
V/mV
Input Voltage Range ±11 ±12 V
CMRR Common Mode Rejection Ratio VCM = ±11V 83 98 dB
PSRR Power Supply Rejection Ratio VS = ±10V to ±18V 88 104 dB
VOUT Output Voltage Swing RL = 2K ±12 ±13.2 V
SR Slew Rate LT1055
LT1056
7.5
9.0
12
14
V/µs
V/µs
GBW Gain Bandwidth Product f = 1MHz LT1055
LT1056
4.5
5.5
MHz
MHz
ISSupply Current LT1055
LT1056
2.8
5.0
4.0
7.0
mA
mA
Offset Voltage Adjustment Range RPOT = 100k ±5 mV
SYMBOL PARAMETER CONDITIONS
LT1055CS8/LT1056CS8
UNITSMIN TYP MAX
VOS Input Offset Voltage (Note 2) l800 2200 µV
Average Temperature Coefficient of Input Offset Voltage l4 15 µV/°C
IOS Input Offset Current Warmed Up, TA = 70°C l18 150 pA
IBInput Bias Current Warmed Up, TA = 70°C l±60 ±400 pA
AVOL Large-Signal Voltage Gain VO = ±10V, RL = 2k l60 250 V/mV
CMRR Common Mode Rejection Ratio VCM = ±10.5V l82 98 dB
PSRR Power Supply Rejection Ratio VS = ±10V to ±18V l87 103 dB
VOUT Output Voltage Swing RL = 2K l±12 ±13.1 V
LT1055/LT1056
6
10556fd
For more information www.linear.com/LT1055
TYPICAL PERFORMANCE CHARACTERISTICS
Input Bias and Offset Currents
vs Temperature
Input Bias Current Over the
Common Mode Range
Distribution of Input Offset
Voltage (N8 Package)
Distribution of Offset Voltage Drift
with Temperature (H Package)* Warm-Up Drift
Long Term Drift of
Representative Units
ELECTRICAL CHARACTERISTICS
For MIL-STD components, please refer to LTC883 data sheet for test
listing and parameters.
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: Offset voltage is measured under two different conditions:
(a) approximately 0.5 seconds after application of power; (b) at TA = 25°C
only, with the chip heated to approximately 38°C for the LT1055 and to
45°C for the LT1056, to account for chip temperature rise when the device
is fully warmed up.
Note 3: 10Hz noise voltage density is sample tested on every lot of A
grades. Devices 100% tested at 10Hz are available on request.
Note 4: This parameter is tested on a sample basis only.
Note 5: Current noise is calculated from the formula: in = (2qlB)1/2, where
q = 1.6 • 10–19 coulomb. The noise of source resistors up to 1GΩ swamps
the contribution of current noise.
Note 6: Offset voltage drift with temperature is practically unchanged when
the offset voltage is trimmed to zero with a 100k potentiometer between
the balance terminals and the wiper tied to V+. Devices tested to tighter
drift specifications are available on request.
AMBIENT TEMPERATURE (°C)
0
INPUT BIAS AND OFFSET CURRENT (pA)
100
300
1000
100
LT1055/56 G01
30
10
325 50 75
125
BIAS OR OFFSET CURRENTS
MAY BE POSITIVE OR NEGATIVE
BIAS CURRENT
OFFSET CURRENT
VS = ±15V
VCM = 0V
WARMED UP
LT1055/56 G02
COMMON MODE INPUT VOLTAGE (V)
–15
–120
INPUT BIAS CURRENT, T
A
= 25°C, T
A
= 70°C (pA)
–80
–40
0
40
120
–10 –5 0 5 10 15
80
–1200
–800
–400
0
400
1200
800
VS = ±15V
WARMED UP
TA = 125°C
TA = 125°C
TA = 25°C
TA = 70°C
TA = 70°C
A = POSITIVE INPUT CURRENT
B = NEGATIVE INPUT CURRENT
A
B
B
A
INPUT BIAS CURRENT, T
A
= 125°C (pA)
INPUT OFFSET VOLTAGE (µV)
–800
NUMBER OF INPUTS
80
100
120
800
LT1055/56 G03
60
40
0–400 0400
20
160
140
–600 –200 200 600
VS = ±15V
TA = 25°C
550 UNITS
TESTED FROM
TWO RUNS
(LT1056)
50% YIELD
TO ±140µV
–10
0
20
60
80
100
–8 04
LT1055/56 G04
40
120
–2 810
–6 –4 2 6
*DISTRIBUTION IN THE PLASTIC (N8) PACKAGE
IS SIGNIFICANTLY WIDER.
VS = ±15V
634 UNITS TESTED
FROM THREE RUNS
50% TO
±1.5µV/°C
TIME AFTER POWER ON (MINUTES)
0
CHANGE IN OFFSET VOLTAGE (µV)
60
80
100
4
LT1055/56 G05
40
20
01235
VS = ±15V
TA = 25°C
LT1056CN8
LT1055CN8
LT1056 H PACKAGE
LT1055 H PACKAGE
TIME (MONTHS)
0
OFFSET VOLTAGE CHANGE (µV)
50
–50
40
–40
30
–30
20
–20
10
–10
0
4
LT1055/56 GO6
1235
VS = ±15V
TA = 25°C
LT1055/LT1056
7
10556fd
For more information www.linear.com/LT1055
TYPICAL PERFORMANCE CHARACTERISTICS
LT1056 Large-Signal Response Small-Signal Response LT1055 Large-Signal Response
Undistorted Output Swing vs
Frequency
Slew Rate, Gain Bandwidth vs
Temperature Output Impedance vs Frequency
0.1Hz to 10Hz Noise Noise vs Chip Temperature Voltage Noise vs Frequency
TIME (SECONDS)
0
NOISE VOLTAGE (1µV/DIVISION)
8
LT1055/56 GO7
24610
LT1056
LT1055
FREQUENCY (MHz)
0.1
0
PEAK-TO-PEAK OUTPUT SWING (V)
6
12
18
24
1 10
LT1055/56 G13
30
LT1055 LT1056
VS = ±15V
TA = 25°C
AV = 1, CL = 100pf, 0.5µs/DIV
5V/DIV
LT1055/56 G10
AV = 1, CL = 100pf, 0.2µs/DIV
20mV/DIV
LT1055/56 G11
AV = 1, CL = 100pf, 0.5µs/DIV
5V/DIV
LT1055/56 G12
CHIP TEMPERATURE (°C)
20
1
2
3
5
7
10
10
20
30
50
70
100
40
LT1055/56 G08
0.1Hz TO 10Hz PEAK-TO-PEAK NOISE (µV/
P-P
)
10 8030 50 60 70
fO = 10kHz
fO = 1kHz
PEAK-TO-PEAK
NOISE
RMS NOISE VOLTAGE DENSITY (nV/√Hz)
TEMPERATURE (°C)
SLEW RATE (V/µS)
GAIN BANDWIDTH PRODUCT (MHz)
20
30
25 75
LT1055/56 G14
10
–25 125
0
10
8
6
4
2
VS = ±15V
fO = 1MHz FOR GBW
LT1056 GBW
LT1055 GBW
LT1055 SLEW
LT1056 SLEW
RMS NOISE VOLTAGE DENSITY (nV/√Hz)
FREQUENCY (Hz)
1
100
30 300
LT1055/56 G09
30
10 3 10 100
300
1000
1000
LT1056
1/f CORNER = 28HZ
LT1055
1/f CORNER
= 20HZ
VS = ±15V
TA = 25°C
FREQUENCY (kHz)
1
0.1
OUTPUT IMPEDANCE (Ω)
1
10
100
10 100
1000
LT1055/56 G15
VS = ±15V
TA = 25°C AV = 100
LT1055 LT1056
LT1055 LT1056
LT1056
AV = 10
LT1055
AV = 1
LT1055/LT1056
8
10556fd
For more information www.linear.com/LT1055
TYPICAL PERFORMANCE CHARACTERISTICS
LT1055 Settling Time LT1056 Settling Time
Common Mode Range vs
Temperature
Common Mode and Power Supply
Rejections vs Temperature
Common Mode Rejection Ratio vs
Frequency
Power Supply Rejection Ratio vs
Frequency
Gain vs Frequency Gain, Phase Shift vs Frequency Voltage Gain vs Temperature
FREQUENCY (Hz)
1
GAIN (dB)
60
80
100
100M
LT1055/56 G16
40
20
–20 100 10k 1M
0
140
120
10 1k 100k 10M
VS = ±15V
TA = 25°C
LT1055 LT1056
SETTLING TIME (µS)
0
OUTPUT VOLTAGE SWING FROM 0V (V)
0
LT1055/56 G19
–5
–10 1 2
5
10
3
10mV
10mV
0.5mV
1mV5mV
5mV 2mV
1mV 0.5mV
VS = ±15V
TA = 25°C
2mV
TEMPERATURE (°C)
CMRR, PSRR (dB)
110
120
25 75
LT1055/56 G22
100
–25
125
90
VS = ±10V TO ±17V FOR PSRR
VS = ±15V, VCM = ±10.5V FOR CMRR
CMRR
PSRR
FREQUENCY (MHz)
1
GAIN (dB)
PHASE SHIFT (DEGREES)
10
10
LT1055/56 G17
0
–10 24
20
100
120
140
160
68
VS = ±15V
TA = 25°C
PHASE
GAIN
LT1055 LT1056
LT1055 LT1056
SETTLING TIME (µS)
0
OUTPUT VOLTAGE SWING FROM 0V (V)
0
LT1055/56 G20
–5
–10 1 2
5
10
3
10mV
10mV
2mV 0.5mV
1mV5mV
5mV
2mV 1mV 0.5mV
VS = ±15V
TA = 25°C
FREQUENCY (Hz)
10
0
CMRR (dB)
20
40
60
80
120
100 1k 10k 100k
LT1055/56 G23
1M
10M
100
VS = ±15V
TA = 25°C
TEMPERATURE (°C)
–25
10
100
30
1000
300
25 75
LT1055/56 G18
VOLTAGE GAIN (V/mV)
–75
125
RL = 1k
RL = 2k
VS = ±15V
VO = ±10V
TEMPERATURE (°C)
–50
–15
BATTERY VOLTAGE (V)
–14
–12
–11
±10
15
12
050 100
LT1055/56 G21
–13
13
14
11
VS = ±15V
FREQUENCY (Hz)
10
80
100
120
10k 1M
LT1055/56 G24
60
40
100 1k 100k
10M
20
0
POWER SUPPLY REJECTION RATIO (dB)
140
TA = 25°C
POSITIVE
SUPPLY
NEGATIVE
SUPPLY
LT1055/LT1056
9
10556fd
For more information www.linear.com/LT1055
Supply Current vs Supply Voltage Output Swing vs Load Resistance Short-Circuit Current vs Time
TYPICAL PERFORMANCE CHARACTERISTICS
APPLICATIONS INFORMATION
The LT1055/LT1056 may be inserted directly into LF155A/
LT355A, LF156A/LT356A, OP-15 and OP-16 sockets.
Offset nulling will be compatible with these devices with
the wiper of the potentiometer tied to the positive supply.
Offset Nulling
example, leakage currents in circuitry external to the op
amp can significantly degrade performance. High quality
insulation should be used (e.g. Teflon, Kel-F); cleaning of
all insulating surfaces to remove fluxes and other resi-
dues will probably be required. Surface coating may be
necessary to provide a moisture barrier in high humidity
environments.
Board leakage can be minimized by encircling the input
circuitry with a guard ring operated at a potential close to
that of the inputs: in inverting configurations the guard ring
should be tied to ground, in noninverting connnections
to the inverting input at pin 2. Guarding both sides of the
–
+
V
+
V
–
OUT
2
34
1
57
RP
6
LT1055/56 AI1
LT1055
LT1056
LT1055/56 AI2
OFFSET
TRIM
OFFSET
TRIM
N/C
GUARD
OUTPUT
INPUTS
V+
V–
1
8
7
6
5
43
2
No appreciable change in offset voltage drift with tem-
perature will occur when the device is nulled with a
potentiometer, RP, ranging from 10k to 200k.
The LT1055/LT1056 can also be used in LF351, LF411,
AD547, AD611, OPA-111, and TL081 sockets, provided
that the nulling cicuitry is removed. Because of the LT1055/
LT1056’s low offset voltage, nulling will not be necessary
in most applications.
Achieving Picoampere/Microvolt Performance
In order to realize the picoampere-microvolt level accuracy
of the LT1055/LT1056 proper care must be exercised. For
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (mA)
4
6
2
0
LT1055/56 G25
2
0510 15
8
TA = –55°C
TA = 125°C
TA = –55°C
TA = 125°C
LT1056
LT1055
25°C
25°C
LOAD RESISTANCE (kΩ)
0.1 0.3
–15
OUTPUT VOLTAGE SWING (V)
–9
–12
–3
–6
3
0
9
6
1 3 10
LT1055/56 G26
15
12
TA = –25°C
TA = –125°C
TA = –55°C
TA = –55°C
TA = –25°C
TA = –125°C
VS = ±15V
TIME FROM OUTPUT SHORT TO GROUND
(MINUTES)
0
–50
SHORT-CIRCUIT CURRENT (mA)
–40
–20
–10
0
50
20
12
LT1055/56 G27
–30
30
40
10
3
TA = –55°C
TA = 25°C
TA = 125°C
TA = 125°C
TA = 25°C
TA = –55°C
SINKING
VS = ±15V
LT1055/LT1056
10
10556fd
For more information www.linear.com/LT1055
APPLICATIONS INFORMATION
printed circuit board is required. Bulk leakage reduction
depends on the guard ring width.
The LT1055/LT1056 has the lowest offset voltage of any
JFET input op amp available today. However, the offset
voltage and its drift with time and temperature are still
not as good as on the best bipolar amplifiers because the
transconductance of FETs is considerably lower than that
of bipolar transistors. Conversely, this lower transcon-
ductance is the main cause of the significantly faster speed
performance of FET input op amps.
Offset voltage also changes somewhat with temperature
cycling. The AM grades show a typical 20µV hysteresis
(30µV on the M grades) when cycled over the –55°C to
125°C temperature range. Temperature cycling from 0°C
to 70°C has a negligible (less than 10µV) hysteresis effect.
The offset voltage and drift performance are also affected
by packaging. In the plastic N8 package the molding com-
pound is in direct contact with the chip, exerting pressure
on the surface. While NPN input transistors are largely
unaffected by this pressure, JFET device matching and drift
are degraded. Consequently, for best DC performance, as
shown in the typical performance distribution plots, the
TO-5 H package is recommended.
Noise Performance
The current noise of the LT1055/LT1056 is practically
immeasurable at 1.8fA/√Hz. At 25°C it is negligible up to
1G of source resistance, RS (compound to the noise of
RS). Even at 125°C it is negligible to 100M of RS.
The voltage noise spectrum is characterized by a low 1/f
corner in the 20Hz to 30Hz range, significantly lower than
on other competitive JFET input op amps. Of particular
interest is the fact that with any JFET IC amplifier, the
frequency location of the 1/f corner is proportional to
the square root of the internal gate leakage currents and,
therefore, noise doubles every 20°C. Furthermore, as il-
lustrated in the noise versus chip temperature curves, the
0.1Hz to 10Hz peak-to-peak noise is a strong function of
temperature, while wideband noise (fO = 1kHz) is practi-
cally unaffected by temperature.
Consequently, for optimum low frequency noise, chip
temperature should be minimized. For example, operat-
ing an LT1056 at ±5V supplies or with a 20°C/W case-
to-ambient heat sink reduces 0.1Hz to 10Hz noise from
typically 2.5µVP-P (±15V, free-air) to 1.5µVP-P. Similiarly,
the noise of an LT1055 will be 1.8µVP-P typically because
of its lower power dissipation and chip temperature.
High Speed Operation
Settling time is measured in the test circuit shown. This test
configuration has two features which eliminate problems
common to settling time measurments: (1) probe capaci-
tance is isolated from the “false summing” node, and (2)
it does not require a “flat top” input pulse since the input
pulse is merely used to steer current through the diode
bridges. For more details, please see Application Note 10.
As with most high speed amplifiers, care should be taken with
supply decoupling, lead dress and component placement.
When the feedback around the op amp is resistive (RF),
a pole will be created with RF, the source resistance and
capacitance (RS, CS), and the amplifier input capacitance
(CIN ≈ 4pF). In low closed-loop gain configurations and
with RS and RF in the kilohm range, this pole can create
excess phase shift and even oscillation. A small capaci-
tor (CF) in parallel with RF eliminates this problem. With
RS (CS + CIN) = RFCF, the effect of the feedback pole is
completely removed.
–
+
RS
RF
C
F
CS
CIN
OUTPUT
LT1055/56 AI03
Phase Reversal Protection
Most industry standard JFET input op amps (e.g., LF155/
LF156, LF351, LF411, OP15/16) exhibit phase reversal at
the output when the negative common mode limit at the
input is exceeded (i.e., from –12V to –15V with ±15V sup-
plies). This can cause lock-up in servo systems. As shown
below, the LT1055/LT1056 does not have this problem
due to unique phase reversal protection circuitry (Q1 on
simplified schematic).
LT1055/LT1056
11
10556fd
For more information www.linear.com/LT1055
APPLICATIONS INFORMATION
Settling Time Test Circuit
0.01 DISC
+
+
+
+
+
–
+
15V
15V
–15V
–15V
15k
15k
15k
15k
10k
4.7k
4.7k
10µF
SOLID
TANTALUM
10µF
SOLID
TANTALUM
10µF
SOLID
TANTALUM
10µF
SOLID TANTALUM
10pF (TYPICAL)
10k
PULSE GEN
INPUT
(5V MIN STEP)
2k
2k
0.01 DISC
0.01 DISC
0.01 DISC
50Ω
2W
LT1055
LT1056
AMPLIFIER
UNDER
TEST
AUT OUTPUT
HP5082-8210
HEWLETT
PACKARD
15V
15V
15V
–15V
= 1N4148 –15V
–15V
1/2
U440
1/2
U440
50Ω
3Ω
3Ω
100Ω
DC ZERO
2N160
2N5160
2N3866
2N3866
LT1055/56 AI04
OUTPUT
TO SCOPE
Voltage Follower with Input Exceeding the Negative
Common Mode Range
Output
LT1055/LT1056
Output
(LF155/LF56, LF441, OP-15/OP-16)Input
–
+2k
–15V
15V
OUTPUT
2
3
4
INPUT
±15V
SINE WAVE
7
6
LT1055/56
LT1055/56 AI05
0.5ms/DIV
10V/DIV
LT1055/56 AI06
0.5ms/DIV
10V/DIV
LT1055/56 AI07
0.5ms/DIV
10V/DIV
LT1055/56 AI08
LT1055/LT1056
12
10556fd
For more information www.linear.com/LT1055
TYPICAL APPLICATIONS †
INPUT
0V TO 10V
LT1055/56 TA03
–
+
11.3k*
EXPONENT
TRIM
2500Ω*
562Ω*
3.57k*
ZERO TRIM
15V
500k
500Ω*
4.7k 1.1k
10k*
3k
10k*
1k*
1k*
4.7k
2
3
4
5
6
–15V
–15V
7
LT1055
15V
500pF
POLYSTYRENE
6
2
3
15V
7
LM301A
15V
6
8
2N3906
2N3904
SAWTOOTH
OUTPUT
LM329
0.01µF
1
42 3
11N148
13
14
15 2.2k
9
7
8
33Ω
TEMPERATURE CONTROL LOOP
SCALE FACTOR
1V IN OCTAVE OUT
*1% METAL FILM RESISTOR
PIN NUMBERED TRANSISTORS = CA3096 ARRAY
–
+
Exponential Voltage-to-Frequency Converter for Music Synthesizers
†For ten additional applications utilizing the
LT1055 and LT1056, please see the LTC1043
data sheet and Application Note 3.
12-Bit Charge Balance A/D Converter
–
+
–
+
28k
33k
14k
74C00
0.003µF
CLK OUTPUT (B)
10k
OUTPUT
(A)
D
PCL
Q
Q
CLK
74C74
1N4148
0.01µF
215V
–15V
7
4
6
3
1N4148 1N4148 15V
10k
2N3904
249k*
0V TO 10V INPUT
COUPLE
THERMALLY
1N4148
6
33k
LM329 10k 15V
2
3
7
4
15V
–15V
LT1055/56 TA04
LT1055
LT1001 CIRCUIT OUTPUT
RATIO fOUT (A)
fCLK (B)
LT1055/LT1056
13
10556fd
For more information www.linear.com/LT1055
TYPICAL APPLICATIONS
Fast, 16-Bit Current ComparatorFast “No Trims” 12-Bit Multiplying CMOS DAC Amplifier
LT1055/56 TA05
R
FEEDBACK
IOUT1
IOUT2
OUTPUT
REFERENCE
IN TYPICAL 12-BIT
CMOS DAC
–
+
LT1055 –
+
–
+
215V
7
6
3
15V
LT1056
4.7k 50k*
INPUT
LT1009
2.5V
100k*
4
–15V
2
HP5082-2810
8
15V
3k
OUTPUT
1
7
4
–15V
LT1011
3
DELAY = 250ns
* = 1% FILM RESISTOR
LT1055/56 TA06
LT1055/56 TA07
2
3
–15V
7
4
6
LT1055
15V
15V
560Ω
15V
–
+
LM329
510Ω
820Ω*
6.2k*
500Ω
0°C ADJ
2k
100°C
ADJ
6.2k*
1k* 1k*
2N2907
2N2222
0.01µF
POLYSTYRENE 510pF 2.7k
10k
10k
4.7k
2N2222
TTL OUTPUT
0kHz TO 1kHz =
0°C TO 100°C
2V
LM134
137Ω*
*1% FILM RESISTOR
Temperature-to-Frequency Converter
LT1055/LT1056
14
10556fd
For more information www.linear.com/LT1055
TYPICAL APPLICATIONS
100kHz Voltage Controlled Oscillator
–
+
–
+
–
+
–
+
X1
X2
U1
U2
COM
VR
Y1
Y2
+V
CC
W
Z1
Z2
GT
UP
–V
+15V
SINE OUT
2VRMS
0kHs TO 100kHs
–15
AD639
2
3
15V
7
6
4
–15V
–15V
68k
68k
10k
4.5k22.1k
1k
LT1056
FINE
DISTORTION
TRIMS
15V
15V 15V
15V
–15V
–15V
–15V
–15V LT1055/56 TA08
50k
10Hz
DISTORTION
TRIM
22M POLYSTYRENE
500pF
7
4
3
2
6
LT1056 22k
15pF
HP5082-
2810 3
2
10k* 10k
1k
4.7k 4.7k
*1% FILM RESISTOR
=1N4148
FREQUENCY LINEARITY = 0.1%
FREQUENCY STABILITY = 150ppm/°C
SETTLING TIME = 1.7µs
DISTORTION = 0.25% AT 100kHz,
0.07% AT 10zHz
1k
5k
FREQUENCY
TRIM
LT1011
8
7
1
4
LM329
0.01µF
2.5k*
10k*
5k*
2N4391
2N4391
2N4391
6
7
4
15V
–15V
LT1056
100kHz
DISTORTION
TRIM
2k
9.09k*
0V TO 10V
INPUT
2
3
10k
20pF
12-Bit Voltage Output D/A Converter
–
+
15V
–15V
7
4
3
2
6
LT1056 OUTPUT
0V TO 10V
CF = 15pF TO 33pF
SETTLING TIME TO 2mV
(0.8 LSB) = 1.5µs TO 2µs
0 TO 2
OR 4mA
12-BIT CURRENT OUTPUT D/A
CONVERTER (e.g., 6012,565
OR DAC-80)
CF
LT1055/56 TA09
LT1055/LT1056
15
10556fd
For more information www.linear.com/LT1055
SIMPLIFIED SCHEMATIC
1
3
2
NULL
5
7
6 OUTPUT
NULL
–
INPUT
+
INPUT
7k 7k
J6 J7
J4
J3
J8
J5
J1 J2
Q7
Q3
Q4
Q8
Q9
Q2
Q1
Q14
Q12
Q11 Q10
Q13
Q15
Q16
400µA*
(1100)
Q5
7.5pF
300Ω
50Ω
3k
V+
4V
–
20Ω
200Ω
800µA*
(1000)
120µA*
(160)
120µA*
(160)
8k
14k14k 9pF
*CURRENTS AS SHOWN FOR LT1055. (X) = CURRENTS FOR LT1056.
LT1055/56 SCHM
LT1055/LT1056
16
10556fd
For more information www.linear.com/LT1055
.050
(1.270)
MAX
.016 – .021**
(0.406 – 0.533)
.010 – .045*
(0.254 – 1.143)
SEATING
PLANE
.040
(1.016)
MAX .165 – .185
(4.191 – 4.699)
GAUGE
PLANE
REFERENCE
PLANE
.500 – .750
(12.700 – 19.050)
.305 – .335
(7.747 – 8.509)
.335 – .370
(8.509 – 9.398)
DIA
.200
(5.080)
TYP
.027 – .045
(0.686 – 1.143)
.028 – .034
(0.711 – 0.864)
.110 – .160
(2.794 – 4.064)
INSULATING
STANDOFF
45°
H8(TO-5) 0.200 PCD 0204
LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE
AND THE SEATING PLANE
FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS .016 – .024
(0.406 – 0.610)
*
**
PIN 1
H Package
8-Lead TO-5 Metal Can (.200 Inch PCD)
(Reference LTC DWG # 05-08-1320)
PACKAGE DESCRIPTION
OBSOLETE PACKAGE
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
LT1055/LT1056
17
10556fd
For more information www.linear.com/LT1055
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
N8 REV I 0711
.065
(1.651)
TYP
.045 – .065
(1.143 – 1.651)
.130 ±.005
(3.302 ±0.127)
.020
(0.508)
MIN
.018 ±.003
(0.457 ±0.076)
.120
(3.048)
MIN
.008 – .015
(0.203 – 0.381)
.300 – .325
(7.620 – 8.255)
.325 +.035
–.015
+0.889
–0.381
8.255
( )
1 2 34
87 65
.255 ±.015*
(6.477 ±0.381)
.400*
(10.160)
MAX
NOTE:
1. DIMENSIONS ARE
INCHES
MILLIMETERS
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm)
.100
(2.54)
BSC
N Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510 Rev I)
LT1055/LT1056
18
10556fd
For more information www.linear.com/LT1055
PACKAGE DESCRIPTION
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
.016 – .050
(0.406 – 1.270)
.010 – .020
(0.254 – 0.508)× 45°
0°– 8° TYP
.008 – .010
(0.203 – 0.254)
SO8 REV G 0212
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
1234
.150 – .157
(3.810 – 3.988)
NOTE 3
8765
.189 – .197
(4.801 – 5.004)
NOTE 3
.228 – .244
(5.791 – 6.197)
.245
MIN .160 ±.005
RECOMMENDED SOLDER PAD LAYOUT
.045 ±.005
.050 BSC
.030
±.005
TYP
INCHES
(MILLIMETERS)
NOTE:
1. DIMENSIONS IN
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610 Rev G)
LT1055/LT1056
19
10556fd
For more information www.linear.com/LT1055
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
REVISION HISTORY
REV DATE DESCRIPTION PAGE NUMBER
D 08/15 Corrected application circuit. 20
(Revision history begins at Rev D)
LT1055/LT1056
20
10556fd
For more information www.linear.com/LT1055
LINEAR TECHNOLOGY CORPORATION 1994
LT 0815 REV D • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LT1055
RELATED PARTS
TYPICAL APPLICATION
±120V Output Precision Op Amp
PART NUMBER DESCRIPTION COMMENTS
LT1122 Fast Settling JFET Op Amp 340ns Settling Time, GBW = 14MHz, SR = 60V/µs
LT1792 Low Noise JFET Op Amp en = 6nV/√Hz Max at f = 1kHz
10k
10k
100pF
LT1055/56 TA10
–
+
7
4
3
2
6
LT1055
10k
INPUT
1N965
1µF 510Ω 330Ω
125V
2N5415
50k
50k
1M
1M
1N4148
1N4148
2N2222
2N2907
1k
1k
2N3440
27Ω
27Ω
OUTPUT
2N5415
2N3440
330Ω
510Ω
1N965
1µF –125V
33pF
100k
10k
±25mA OUTPUT
HEAT SINK OUTPUT
TRANSISTORS