LINER LTC1049CN8 Low power zero-drift operational amplifier Datasheet

LTC1049
Low Power Zero-Drift
Operational Amplifier
with Internal Capacitors
Description
Features
n
n
n
n
n
n
n
n
n
Low Supply Current: 200µA
No External Components Required
Maximum Offset Voltage: 10µV
Maximum Offset Voltage Drift: 0.1µV/°C
Single Supply Operation: 4.75V to 16V
Input Common Mode Range Includes Ground
Output Swings to Ground
Typical Overload Recovery Time: 6ms
Available in 8-Pin SO and PDIP Packages
The LTC®1049 is a high performance, low power zero-drift
operational amplifier. The two sample-and-hold capacitors
usually required externally by other chopper stabilized
amplifiers are integrated on the chip. Further, the LTC1049
offers superior DC and AC performance with a nominal
supply current of only 200µA.
The LTC1049 has a typical offset voltage of 2µV, drift of
0.02µV/°C, 0.1Hz to 10Hz input noise voltage of 3µVP-P
and typical voltage gain of 160dB. The slew rate is 0.8V/µs
with a gain bandwidth product of 0.8MHz.
Applications
n
n
n
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n
Overload recovery time from a saturation condition is
6ms, a significant improvement over chopper amplifiers
using external capacitors.
4mA to 20mA Current Loops
Thermocouple Amplifiers
Electronic Scales
Medical Instrumentation
Strain Gauge Amplifiers
High Resolution Data Acquisition
The LTC1049 is available in a standard 8-pin plastic dual
in line, as well as an 8-pin SO package. The LTC1049 can
be a plug-in replacement for most standard op amps with
improved DC performance and substantial power savings.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Typical Application
Single Supply Thermocouple Amplifier
0.068µF
VIN = 5V
246k
1k
2
2
K
LT ®1025A
GND
4
R–
5
7
–
+
TYPE K
3
–
7
LTC1049
+
6
VOUT = 0V TO 4V
FOR 0°C TO 400°C
4
0.1µF
SUPPLY CURRENT = 280µA
LTC1049 • TA01
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1
LTC1049
Absolute Maximum Ratings
(Note 1)
Total Supply Voltage (V + to V –).................................18V
Input Voltage (Note 2).............(V+ + 0.3V) to (V – – 0.3V)
Output Short-Circuit Duration........................... Indefinite
Operating Temperature Range..................–40°C to 85°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec).................... 300°C
Package/order information
TOP VIEW
NC 1
8
NC
–IN 2
7
V+
+IN 3
6
OUT
V– 4
5
NC
ORDER PART
NUMBER
LTC1049CN8
NC 1
–IN 2
+IN 3
V–
N8 PACKAGE 8-LEAD PDIP
TJMAX = 110°C, θJA = 130°C/W
LTC1049CJ8
J8 PACKAGE 8-LEAD CERDIP
TJMAX = 150°C, θJA = 100°C/W
OBSOLETE PACKAGE
ORDER PART
NUMBER
TOP VIEW
4
–
+
8
NC
7
V+
6
OUT
5
NC
LTC1049CS8
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
1049
TJMAX = 110°C, θJA = 200°C/W
Consider the N8 Package as an Alternate Source
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VS = ±5V, unless noted.
PARAMETER
CONDITIONS
Input Offset Voltage
Average Input Offset Drift
Long Term Offset Voltage Drift
Input Offset Current
(Note 3)
(Note 3)
MIN
l
TYP
MAX
UNITS
±2
±0.02
50
±30
±10
±0.1
µV
µV/°C
nV√mo
pA
pA
pA
pA
µVP-P
µVP-P
fA√Hz
dB
dB
dB
V
V
V
V/µs
MHz
µA
µA
Hz
l
±15
Input Bias Current
l
Input Noise Voltage
Input Noise Current
Common Mode Rejection Ratio
Power Supply Rejection Ratio
Large-Signal Voltage Gain
Maximum Output Voltage Swing
0.1Hz to 10Hz
0.1Hz to 1Hz
f = 10Hz (Note 4)
VCM = V – to 2.7V
VS = ±2.375V to ±8V
RL = 100kΩ, VOUT = ±4.75V
RL = 10kΩ
l
l
l
l
Slew Rate
Gain Bandwidth Product
Supply Current
RL = 100kΩ
RL = 10kΩ, CL = 50pF
l
No Load
110
110
130
–4.6/3.2
±4.9
3
1
2
130
130
160
–4.9/4.2
±4.97
0.8
0.8
200
l
Internal Sampling Frequency
±100
±150
±50
±150
700
330
495
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2
LTC1049
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: Connecting any terminal to voltages greater than V + or less than
V – may cause destructive latch-up. It is recommended that no sources
operating from external supplies be applied prior to power-up of the
LTC1049.
Note 3: These parameters are guaranteed by design. Thermocouple effects
preclude measurement of these voltage levels in high speed automatic
test systems. VOS is measured to a limit determined by test equipment
capability.
Note 4: Current Noise is calculated from the formula:
IN = √(2q • Ib)
where q = 1.6 • 10–19 Coulomb.
Typical Performance Characteristics
Common Mode Input Range vs
Supply Voltage
Voltage Noise vs Frequency
140
8
60
40
100
10
1k
10k
2
0
–2
60
40
–6
–20
200
0
1
4
5
2
3
6
SUPPLY VOLTAGE (±V)
7
8
–40
100
SHORT-CIRCUIT OUTPUT CURRENT (mA)
SUPPLY CURRENT (µA)
SUPPLY CURRENT (µA)
300
200
100
6
7 8 9 10 11 12 13 14 15
TOTAL SUPPLY VOLTAGE (V)
LTC1049 • TPC04
0
–50 –25
220
10M
1.2
400
5
1M
Output Short-Circuit Current vs
Supply Voltage
500
100
10k
100k
FREQUENCY (Hz)
LTC1049 • TPC03
Supply Current vs Temperature
400
160
1k
LTC1049 • TPC02
Supply Current vs Supply Voltage
220
160
180
LTC1049 • TP01
280
140
GAIN
20
120
0
FREQUENCY (Hz)
340
100
PHASE
–4
–8
100k
80
80
4
VOLTAGE GAIN (dB)
COMMON MODE VOLTAGE (V)
VOLTAGE NOISE (nV/√Hz)
80
60
VS = ±5V
100 NO LOAD
PHASE SHIFT (DEGREES)
100
20
VCM = V –
6
120
Gain/Phase vs Frequency
120
50
25
0
75
TEMPERATURE (°C)
100
125
LTC1049 • TPC05
0.8
0.4
0
≈
≈
–3
–6
–9
4
8
10
12
14
6
TOTAL SUPPLY VOLTAGE, V+ TO V–(V)
16
LTC1049 • TPC06
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3
LTC1049
Typical Performance Characteristics
Sampling Frequency vs
Supply Voltage
Sampling Frequency vs
Temperature
5
3000
CMRR vs Frequency
160
VS = ±5V
VS = ±5V
2500
2000
1500
4
120
3
CMRR (dB)
SAMPLING FREQUENCY (kHz)
SAMPLING FREQUENCY (Hz)
140
2
100
80
60
40
1
20
1000
4
0
50
25
0
75 100
–50 –25
AMBIENT TEMPERATURE (°C)
14
16
6
8
10
12
TOTAL SUPPLY VOLTAGE, V + TO V – (V)
125
0
1
10
100
1k
FREQUENCY (Hz)
10k
LTC1049 • TPC09
LTC1049 • TPC08
LTC1049 • TPC07
Small-Signal Transient
Response
Overload Recovery
100k
Large-Signal Transient
Response
400mV
INPUT
100mV
STEP
6V
STEP
OUTPUT
0.2V/DIV
1µs/DIV
5µs/DIV
0V
0V
2V/DIV
–5V
AV = –100
VS = ±5V
0.5ms/DIV
LTC1049 • TPC10
AV = 1
RL = 10k
CL = 50pF
VS = ±5V
LTC1049 • TPC11
AV = 1
RL = 10k
CL = 50pF
VS = ±5V
LTC1049 • TPC12
LTC1049 DC to 1Hz Noise
VS = ±5V
1Hz NOISE
1µV/DIV
NOISE VOLTAGE
1µV/DIV
10s/DIV
LTC1049 • TPC13
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LTC1049
Typical Performance Characteristics
LTC1049 DC to 10Hz Noise
VS = ±5V
NOISE VOLTAGE
1µV/DIV
10Hz NOISE
1µV/DIV
1s/DIV
LTC1049•TPC14
Test Circuits
Electrical Characteristics Test Circuit
DC to 10Hz and DC to 1Hz Noise Test Circuit
140
8
COMMON MODE VOLTAGE (V)
VOLTAGE NOISE (nV/√Hz)
120
100
80
60
40
20
VCM = V –
6
4
2
0
–2
–4
–6
10
100
1k
10k
100k
FREQUENCY (Hz)
LTC1049 • TP01
–8
0
1
4
5
2
3
6
SUPPLY VOLTAGE (±V)
7
8
LTC1049 • TPC02
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LTC1049
Applications Information
ACHIEVING PICOAMPERE/MICROVOLT PERFORMANCE
Picoamperes
In order to realize the picoampere level of accuracy of
the LTC1049, proper care must be exercised. Leakage
currents in circuitry external to the amplifier 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 residues will probably
be necessary—particularly for high temperature perfor­
mance. Surface coating may be necessary to provide a
moisture barrier in high humidity environments.
Board leakage can be minimized by encircling the input
connections 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 connections,
to the inverting input. Guarding both sides of the printed
circuit board is required. Bulk leakage reduction depends
on the guard ring width.
Microvolts
Thermocouple effects must be considered if the LTC1049’s
ultralow drift is to be fully utilized. Any connection of dissimilar metals forms a thermoelectric junction produc­ing an
electric potential which varies with temperature (Seebeck
effect). As temperature sensors, thermocouples exploit this
phenomenon to produce useful information. In low drift
amplifier circuits the effect is a primary source of error.
Connectors, switches, relay contacts, sockets, resistors,
solder, and even copper wire are all candidates for thermal
EMF generation. Junctions of copper wire from different
manufacturers can generate thermal EMFs of 200nV/°C —
twice the maximum drift specification of the LTC1049.
The copper/kovar junction, formed when wire or printed
circuit traces contact a package lead, has a thermal EMF
of approximately 35µV/°C—300 times the maximum drift
specification of the LTC1049.
Minimizing thermal EMF-induced errors is possible if
judicious attention is given to circuit board layout and
component selection. It is good practice to minimize the
number of junctions in the amplifier’s input signal path.
Avoid connectors, sockets, switches, and relays where
possible. In instances where this is not possible, attempt to
balance the number and type of junctions so that differential
cancellation occurs. Doing this may involve deliberately
introducing junctions to offset unavoidable junctions.
PACKAGE-INDUCED OFFSET VOLTAGE
Package-induced thermal EMF effects are another
impor­tant source of errors. It arises at the copper/kovar
junctions formed when wire or printed circuit traces contact
a pack­age lead. Like all the previously mentioned thermal
EMF effects, it is outside the LTC1049’s offset nulling loop
and cannot be cancelled. The input offset voltage specification of the LTC1049 is actually set by the package-induced
warm-up drift rather than by the circuit itself. The thermal
time constant ranges from 0.5 to 3 minutes, depending
on package type.
LOW SUPPLY OPERATION
The minimum supply for proper operation of the LTC1049
is typically below 4.0V (±2.0V). In single supply applica­
tions, PSRR is guaranteed down to 4.7V (±2.35V) to ensure
proper operation down to the minimum TTL specified
voltage of 4.75V.
PIN COMPATIBILITY
The LTC1049 is pin compatible with the 8-pin versions of
7650, 7652 and other chopper-stabilized amplifiers. The
7650 and 7652 require the use of two external capacitors
connected to Pins 1 and 8 which are not needed for the
LTC1049. Pins 1, 5, and 8 of the LTC1049 are not connected
internally; thus, the LTC1049 can be a direct plug- in for
the 7650 and 7652, even if the two capacitors are left on
the circuit board.
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LTC1049
Typical Applications
Low Power, Low Hold Step Sample-and-Hold
5V
13
2
4.5
LTC201
VIN
S/H
3
2
1
3
–
5V
7
LTC1049
+
0.47µF
MYLAR
4
6
VOUT
DROOP ≤1mV/s
HOLD STEP ≤20µV
IS = 250µA TYP
LTC1049 • TA02
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LTC1049
Typical Applications
Low Power, Single Supply, Low Offset Instrumentation Amp
5V
198k
2k
2
–
– VIN
+
198k
2
7
LTC1049
3
2k
6
–
7
LTC1049
3
4
+
6
VOUT
4
+ VIN
GAIN = 100
IS = 400µA
CMRR ≥ 60dB, WITH 0.1% RESISTORS (RESISTORS LIMITED)
LTC1049 • TA03
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LTC1049
Package Description
J8 Package
8-Lead CERDIP (Narrow .300 Inch, Hermetic)
(Reference LTC DWG # 05-08-1110)
CORNER LEADS OPTION
(4 PLCS)
.023 – .045
(0.584 – 1.143)
HALF LEAD
OPTION
.045 – .068
(1.143 – 1.650)
FULL LEAD
OPTION
.005
(0.127)
MIN
.405
(10.287)
MAX
8
7
6
5
.025
(0.635)
RAD TYP
.220 – .310
(5.588 – 7.874)
1
.300 BSC
(7.62 BSC)
2
3
4
.200
(5.080)
MAX
.015 – .060
(0.381 – 1.524)
.008 – .018
(0.203 – 0.457)
0° – 15°
NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE
OR TIN PLATE LEADS
.045 – .065
(1.143 – 1.651)
.014 – .026
(0.360 – 0.660)
.100
(2.54)
BSC
.125
3.175
MIN
J8 0801
OBSOLETE PACKAGE
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LTC1049
Package Description
N8 Package
8-Lead PDIP (Narrow .300 Inch)
(Reference LTC DWG # 05-08-1510)
.400*
(10.160)
MAX
8
7
6
5
1
2
3
4
.255 ± .015*
(6.477 ± 0.381)
.300 – .325
(7.620 – 8.255)
.008 – .015
(0.203 – 0.381)
(
+.035
.325 –.015
8.255
+0.889
–0.381
)
.045 – .065
(1.143 – 1.651)
.065
(1.651)
TYP
.100
(2.54)
BSC
.130 ± .005
(3.302 ± 0.127)
.120
(3.048) .020
MIN
(0.508)
MIN
.018 ± .003
(0.457 ± 0.076)
N8 1002
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)
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LTC1049
Package Description
S8 Package
8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference LTC DWG # 05-08-1610)
.050 BSC
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
8
.245
MIN
.160 ±.005
5
.150 – .157
(3.810 – 3.988)
NOTE 3
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
2
3
4
.053 – .069
(1.346 – 1.752)
.004 – .010
(0.101 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
6
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
.008 – .010
(0.203 – 0.254)
7
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
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)
.050
(1.270)
BSC
SO8 0303
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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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LTC1049
Typical Application
Thermocouple-Based Temperature to Frequency Converter
6V
V+
GND
–
– +
1M
LTC1049
R–
Q2
2N3906
+
6.81k*
Q1
2N3904
NC
10k
100k
K
LT1025
6V
0.02µF
TYPE K
THERMOCOUPLE
l1
l2
100k
C1
100pF
C3
0.47µF
1.5k
240k
+
100°C
TRIM
C4
300pF
6V
9
11
14
C2
390pF †
S1
10
S4
IS = 360µA
SUPPLY RANGE = 4.5V to 10V
S2
3
*IRC/TRW–MTR–5/+120ppm
†POLYSTYRENE
= 74C14
S3
2
OUTPUT
0 – 100°C =
0 – 1kHz
LT1004 – 1.2
6.8µF
16
15
l3
6
7
LTC201
1
8
LTC1049 • TA04
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12 Linear Technology Corporation
LT 0406 REV B • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
 LINEAR TECHNOLOGY CORPORATION 1991
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