LT1122
Fast Settling, JFET Input
Operational Amplifier
FEATURES
n
DESCRIPTION
340ns Typ
540ns Max
60V/µs Min
14MHz
1.2 MHz
60°
600µV Max
75pA Max
600pA Max
40pA Max
150pA Max
The
LT
®
1122
JFET input operational amplifier combines
high speed and precision performance.
A unique poly-gate JFET process minimizes gate series
resistance and gate-to-drain capacitance, facilitating wide
bandwidth performance, without degrading JFET transis-
tor matching.
It slews at 80V/µs and settles in 340ns. The LT1122 is
internally compensated to be unity-gain stable, yet it has
a bandwidth of 14MHz at a supply current of only 7mA. Its
speed makes the LT1122 an ideal choice for fast settling
12-bit data conversion and acquisition systems.
The LT1122 offset voltage of 120µV, and voltage gain of
500,000 also support the 12-bit accurate applications.
The input bias current of 10pA and offset current of 4pA
combined with its speed allow the LT1122 to be used in
such applications as high speed sample and hold ampli-
fiers, peak detectors, and integrators.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and C-Load
is a trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
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■
■
100% Tested Settling Time
to 1mV at Sum Node, 10V Step
Tested with Fixed Feedback Capacitor
Slew Rate
Gain-Bandwidth Product
Power Bandwidth (20V
P-P
)
Unity-Gain Stable; Phase Margin
Input Offset Voltage
Input Bias Current
25°C
70°C
Input Offset Current
25°C
70°C
Low Distortion
APPLICATIONS
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Fast 12-Bit D/A Output Amplifiers
High Speed Buffers
Fast Sample-and-Hold Amplifiers
High Speed Integrators
Voltage to Frequency Converters
Active Filters
Log Amplifiers
Peak Detectors
TYPICAL APPLICATION
12-Bit Voltage Output D/A Converter
+
Large-Scale Response
CF
2
0mA TO 2mA
OR 4mA
3
LT1122
6
+
V
OUT
0V TO 10V
12-BIT CURRENT OUTPUT D/A CONVERTER
C
F
= 5pF TO 17pF
(DEPENDING ON D/A CONVERTER USED)
5V/DIV
–
LT1122•TA01
200ns/DIV
A
V
= –1
1122 TA07
1122fb
For more information
www.linear.com/LT1122
1
LT1122
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage ...................................................... ± 20V
Differential Input Voltage ....................................... ± 40V
Input Voltage.......................................................... ± 20V
Output Short Circuit Duration .......................... Indefinite
Lead Temperature (Soldering, 10 sec.).................. 300°C
Operating Temperature Range
LT1122AM/BM/CM/DM
(OBSOLETE)
.. –55°C to 125°C
LT1122AC/BC/CC/DC/CS/DS .................–40°C to 85°C
Storage Temperature Range
All Devices .......................................... –65°C to 150°C
PIN CONFIGURATION
TOP VIEW
V
OS
1
TRIM
–IN 2
+IN 3
V
–
8
7
6
5
N8 PACKAGE
8-LEAD PDIP
SPEED BOOST/
OVERCOMP
V
+
OUT
V
OS
TRIM
TOP VIEW
V
OS
1
TRIM
–IN 2
+IN 3
V
–
4
8
7
6
5
SPEED BOOST/
OVERCOMP
V
+
OUT
V
OS
TRIM
4
T
JMAX
= 150°C,
θ
JA
= 130°C/W
J8 PACKAGE 8-LEAD HERMETIC DIP
T
JMAX
= 175°C,
θ
JA
= 100°C/W
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 190°C/W
OBSOLETE PACKAGE
ORDER INFORMATION
LEAD FREE FINISH
LT1122ACN8#PBF
LT1122BCN8#PBF
LT1122CCN8#PBF
LT1122DCN8#PBF
LT1122CS8#PBF
LT1122DS8#PBF
LT1122AMJ8#PBF
LT1122BMJ8#PBF
LT1122CMJ8#PBF
LT1122DMJ8#PBF
LT1122ACJ8#PBF
LT1122BCJ8#PBF
LT1122CCJ8#PBF
LT1122DCJ8#PBF
TAPE AND REEL
LT1122ACN8#TRPBF
LT1122BCN8#TRPBF
LT1122CCN8#TRPBF
LT1122DCN8#TRPBF
LT1122CS8#TRPBF
LT1122DS8#TRPBF
LT1122AMJ8#TRPBF
LT1122BMJ8#TRPBF
LT1122CMJ8#TRPBF
LT1122DMJ8#TRPBF
LT1122ACJ8#TRPBF
LT1122BCJ8#TRPBF
LT1122CCJ8#TRPBF
LT1122DCJ8#TRPBF
PART MARKING
LT1122ACN8
LT1122BCN8
LT1122CCN8
LT1122DCN8
1122C
1122D
LT1122AMJ8
LT1122BMJ8
LT1122CMJ8
LT1122DMJ8
LT1122ACJ8
LT1122BCJ8
LT1122CCJ8
LT1122DCJ8
PACKAGE DESCRIPTION
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead Plastic DIP
8-Lead Plastic SO
8-Lead Plastic SO
OBSOLETE PACKAGE
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
8-Lead Hermetic DIP
–55°C to 125°C
–55°C to 125°C
–55°C to 125°C
–55°C to 125°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°C
–40°C to 85°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/
1122fb
2
For more information
www.linear.com/LT1122
LT1122
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
S
= ±15V, V
CM
= 0V unless otherwise noted. (Note 2)
LT1122AM/BM
LT1122AC/BC
MIN TYP MAX
120
4
10
10
12
10
12
10
11
4
A
V
= – 1
10V to 0V, – 10V to 0V
100% Tested: A- and C-Grades to 1mV at Sum Node
B- and D-Grades to 1mV at Sum Node
All Grades to 0.5mV at Sum Node
60
80
340
350
450
14
1.2
180
130
83
±10.5
86
500
250
99
±11
103
3.0
25
14
2
±12 ±12.5
±11.5 ±12
7.5
(Note 5)
R
POT
≥ 10k, Wiper to V
+
±5
±4
±10
10
±5
±4
±10
150
110
80
±10.5
82
540
50
600
40
75
LT1122CM/DM
LT1122CC/DC
LT1122CS/DS
MIN TYP MAX
130
5
12
10
12
10
12
10
11
4
75
350
360
470
13
1.1
450
220
98
±11
101
3.3
27
15
2
±12 ±12.5
±11.5 ±12
7.8
11
590
900
50
100
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
OS
I
OS
I
B
Input Offset Voltage
Input Offset Current
Input Bias Current
Input Resistance
Differential
Common Mode
Input Capacitance
SR
Slew Rate
Settling Time (Note 2)
CONDITIONS
UNITS
µV
pA
pA
Ω
Ω
Ω
pF
V/µs
ns
ns
ns
MHz
MHz
V/mV
V/mV
dB
V
dB
µV
P-P
nV/√Hz
nV/√Hz
fA/√Hz
V
V
mA
V
mV
V
CM
= –10V to 8V
V
CM
= 8V to 11V
GBW
A
VOL
CMRR
PSRR
Gain-Bandwidth Product Power
Bandwidth
V
OUT
= 20V
P-P
Large-Signal Voltage Gain
V
OUT
= ±10V, R
L
= 2kΩ
V
OUT
= ±10V, R
L
= 600Ω
(Note 4)
V
S
= ±10V to ±18V
0.1Hz to 10Hz
f
O
= 100Hz
f
O
= 10kHz
f
O
= 100Hz, f
O
= 10kHz
R
L
= 2kΩ
R
L
= 600Ω
Common-Mode Rejection Ratio V
CM
= ±10V
Input Voltage Range
Power Supply Rejection Ratio
Input Noise Voltage
Input Noise Voltage Density
Input Noise Current Density
V
OUT
I
S
Output Voltage Swing
Supply Current
Minimum Supply Voltage
Offset Adjustment Range
1122fb
For more information
www.linear.com/LT1122
3
LT1122
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at 0°C ≤ T
A
≤ 70°C. V
S
= ±15V, V
CM
= 0V. (Note 2)
LT1122AC/BC
MIN
TYP
MAX
l
l
l
l
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
V
OS
Input Offset Voltage
Average Temperature Coefficient of
Input Offset Voltage
I
OS
IB
A
VOL
CMRR
PSRR
V
OUT
SR
Input Offset Current
Input Bias Current
Large-Signal Voltage Gain
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Input Voltage Range
Output Voltage Swing
Slew Rate
R
L
= 2kΩ
A
V
= –1
CONDITIONS
LT1122CC/DC
LT1122CS/DS
MIN
TYP
MAX
400
6
15
90
100
78
80
±10
±11.5
40
340
96
99
±10.8
±12.4
65
2000
25
200
800
UNITS
µV
µV/°C
pA
pA
V/mV
dB
dB
V
V
V/µs
350
5
12
80
120
82
84
±10
±11.5
50
380
98
101
±10.8
±12.4
70
1400
18
150
600
V
OUT
= ±10V, R
L
≥ 2kΩ
V
CM
= ±10V
V
S
= ±10V to ±17V
l
l
l
l
l
l
The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications
are at –55°C ≤ T
A
≤ 125°C. V
S
= ±15V, V
CM
= 0V. (Note 2)
SYMBOL PARAMETER
V
OS
Input Offset Voltage
Average Temperature Coefficient of
Input Offset Voltage
I
OS
I
B
A
VOL
CMRR
PSRR
V
OUT
SR
Input Offset Current
Input Bias Current
Large-Signal Voltage Gain
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Input Voltage Range
Output Voltage Swing
Slew Rate
R
L
= 2kΩ
A
V
= –1
V
OUT
= ±10V, R
L
≥ 2kΩ
V
CM
= ±10V
V
S
= ±10V to ±17V
CONDITIONS
l
l
l
l
l
l
l
l
l
l
LT1122AM/BM
MIN
TYP
MAX
650
6
0.5
6
70
80
83
±10
±11.3
45
230
97
100
±10.5
±12.1
60
2400
18
6
25
LT1122CS/DS
MIN
TYP
MAX
800
7
0.6
7
60
76
78
±10
±11.3
35
200
94
98
±10.5
±12.1
55
3400
25
9
35
UNITS
µV
µV/°C
nA
nA
V/mV
dB
dB
V
V
V/µs
The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications
are at –40°C ≤ T
A
≤ 85°C. V
S
= ±15V, V
CM
= 0V. (Note 6)
SYMBOL PARAMETER
V
OS
Input Offset Voltage
Average Temperature Coefficient of
Input Offset Voltage
I
OS
I
B
A
VOL
CMRR
PSRR
V
OUT
SR
Input Offset Current
Input Bias Current
Large-Signal Voltage Gain
Common-Mode Rejection Ratio
Power Supply Rejection Ratio
Input Voltage Range
Output Voltage Swing
Slew Rate
R
L
= 2kΩ
A
V
= –1
V
OUT
= ±10V, R
L
≥ 2kΩ
V
CM
= ±10V
V
S
= ±10V to ±17V
CONDITIONS
l
l
l
l
l
l
l
l
l
l
LT1122AM/BM
MIN
TYP
MAX
450
6
30
230
95
80
83
±10
±11.3
45
340
98
100
±10.6
±12.2
60
1900
20
600
2000
LT1122CS/DS
MIN
TYP
MAX
500
7
40
260
80
76
78
±10
±11.3
35
300
96
98
±10.6
±12.2
60
2700
28
900
2700
UNITS
µV
µV/°C
pA
pA
V/mV
dB
dB
V
V
V/µs
1122fb
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For more information
www.linear.com/LT1122
LT1122
ELECTRICAL CHARACTERISTICS
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:
The LT1122 is measured in an automated tester in less than one
second after application of power. Depending on the package used, power
dissipation, heat sinking, and air flow conditions, the fully warmed up chip
temperature can be 10°C to 50°C higher than the ambient temperature.
Note 3:
Settling time is 100% tested for A- and C-grades using the settling
time test circuit shown. This test is not included in quality assurance
sample testing.
Note 4:
Input voltage range functionality is assured by testing offset
voltage at the input voltage range limits to a maximum of 4mV
(A, B grades), to 5.7mV (C, D grades).
Note 5:
Minimum supply voltage is tested by measuring offset voltage to
7mV maximum at ±5V supplies.
Note 6:
The LT1122 is not tested and 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.
Settling Time Test Fixture
DEVICE UNDER TEST
5pF
10V
(REGULATED)
51
4
74LS00
GROUND ALL
OTHER INPUTS
5
2
15
4
16
15V
7
1
HA5002
2
5
–15V
8
51
2k
1%
2
2k
1%
15V
–
+
7
LT1122
6
6
1
3
4
–15V
3
14
V
IN
(MEASURE INPUT
PULSE HERE)
5.1k*
1%
5.1k
1%
TTL
IN
1
2
4
3
5
LTC201A
13
12
6
11
7
10
8
9
15V
7
+
3 51
8
1
HA5002
2
–
2
–15V
79
1N5712
5
4 51
SUMMING
NODE
OUTPUT
–10V
(REGULATED)
15V
0.1µF
NO CONNECTION ON PINS
10, 11, 12, 14, AND 15
1k
SETTLING
TIME OUTPUT
(20 TIMES SUM
NODE OUTPUT)
1N5712
6
15V
7
LT1223
4
1.5k –15V
+
1µF TANT
TYPICAL SUPPLY
BYPASSING FOR
EACH AMP/BUFFER
–15V
0.1µF
1µF TANT
*THIS RESISTOR CAN BE ADJUSTED TO
NULL OUT ALL OFFSETS AT THE SETTLING
TIME OUTPUT. THE AUTOMATED TESTER
USES A SEPARATE AUTOZERO CIRCUIT.
+
LT1122•TA02
1122fb
For more information
www.linear.com/LT1122
5
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