LTC2057/LTC2057HV
High Voltage, Low Noise
Zero-Drift Operational Amplifier
Description
Features
Supply Voltage Range
n 4.75V to 36V (LTC2057)
n 4.75V to 60V (LTC2057HV)
n Offset Voltage: 4μV (Maximum)
n Offset Voltage Drift: 0.015μV/°C
(Maximum, –40°C to 125°C)
n Input Noise Voltage
n 200nVP-P, DC to 10Hz (Typ)
n 11nV/√Hz, 1kHz (Typ)
n Input Common Mode Range: V– – 0.1V to V+ – 1.5V
n Rail-to-Rail Output
n Unity Gain Stable
n Gain Bandwidth Product: 1.5MHz (Typ)
n Slew Rate: 0.45V/μs (Typ)
n A
VOL: 150dB (Typ)
n PSRR: 160dB (Typ)
n CMRR: 150dB (Typ)
n Shutdown Mode
n
Applications
n
n
n
n
n
n
n
n
The LTC®2057 is a high voltage, low noise, zero-drift operational amplifier that offers precision DC performance
over a wide supply range of 4.75V to 36V or 4.75V to
60V for the LTC2057HV. Offset voltage and 1/f noise are
suppressed, allowing this amplifier to achieve a maximum
offset voltage of 4μV and a DC to 10Hz input noise voltage of 200nVP-P (typ). The LTC2057’s self-calibrating
circuitry results in low offset voltage drift with temperature,
0.015μV/°C (max), and zero-drift over time. The amplifier
also features an excellent power supply rejection ratio
(PSRR) of 160dB and a common mode rejection ratio
(CMRR) of 150dB (typ).
The LTC2057 provides rail-to-rail output swing and an
input common mode range that includes the V– rail (V– –
0.1V to V+ – 1.5V). In addition to low offset and noise, this
amplifier features a 1.5MHz (typ) gain-bandwidth product
and a 0.45V/μs (typ) slew rate.
Wide supply range, combined with low noise, low offset,
and excellent PSRR and CMRR make the LTC2057 and
LTC2057HV well suited for high dynamic-range test,
measurement, and instrumentation systems.
High Resolution Data Acquisition
Reference Buffering
Test and Measurement
Electronic Scales
Thermocouple Amplifiers
Strain Gauges
Low-Side Current Sense
Automotive Monitors and Control
L, LT, LTC, LTM, Linear Technology, Over-The-Top, and the Linear logo are registered
trademarks of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
Typical Application
Wide Input Range Precision Gain-of-100 Instrumentation Amplifier
Input Offset Voltage
vs Supply Voltage
30V
–IN
5
+
5 TYPICAL UNITS
4 VCM = VS /2
T = 25°C
3 A
LTC2057HV
–
18V
232Ω
11.5k
11.5k
30V
–
LTC2057HV
+IN
+
8
M9
9
M3
10
M1
1
P1
2
P3
3
P9
2
7
VOS (µV)
–30V
VCC
LT1991A
VEE
4
–18V
OUT
6
VOUT
REF
5
1
0
–1
–2
–3
–4
–5
2057 TA01a
INPUT CM RANGE = ±28V WITH 4V OF OUTPUT SWING
CMRR = 130dB (TYP), INPUT OFFSET VOLTAGE = 1µV (TYP)
0 5 10 15 20 25 30 35 40 45 50 55 60 65
VS (V)
2057 TA01b
–30V
2057f
For more information www.linear.com/LTC2057
1
LTC2057/LTC2057HV
Absolute Maximum Ratings
(Note 1)
Total Supply Voltage (V+ to V–)
LTC2057 ...............................................................40V
LTC2057HV............................................................65V
Input Voltage
–IN, +IN.................................... V– – 0.3V to V+ + 0.3V
SD, SDCOM ............................. V– – 0.3V to V+ + 0.3V
Input Current
–IN, +IN............................................................ ±10mA
SD, SDCOM...................................................... ±10mA
Differential Input Voltage
–IN – +IN��������������������������������������������������������������±6V
SD – SDCOM......................................... –0.3V to 5.3V
Output Short-Circuit Duration........................... Indefinite
Operating Temperature Range (Note 2)
LTC2057I/LTC2057HVI.........................–40°C to 85°C
LTC2057H/LTC2057HVH.................... –40°C to 125°C
Storage Temperature Range................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................... 300°C
Pin Configuration
TOP VIEW
SD
1
–IN
2
+IN
3
V–
4
–
+
9
V–
8 SDCOM
TOP VIEW
7 V+
SD
–IN
+IN
V–
6 OUT
5 NC
1
2
3
4
–
+
8
7
6
5
SDCOM
V+
OUT
NC
MS8 PACKAGE
8-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 163°C/W
DD PACKAGE
8-LEAD (3mm × 3mm) PLASTIC DFN
TJMAX = 150°C, θJA = 43°C/W
EXPOSED PAD (PIN 9) IS V–
PCB CONNECTION REQUIRED
TOP VIEW
SD 1
–IN 2
+IN 3
V–
4
–
+
8
SDCOM
7
V+
6
OUT
5
NC
TOP VIEW
GRD
–IN
+IN
GRD
V–
1
2
3
4
5
–
+
10
9
8
7
6
SD
SDCOM
V+
NC
OUT
MS PACKAGE
10-LEAD PLASTIC MSOP
TJMAX = 150°C, θJA = 160°C/W
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 150°C, θJA = 120°C/W
2057f
2
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2057IDD#PBF
LTC2057IDD#TRPBF
LGCZ
8-Lead Plastic DFN (3mm × 3mm)
–40°C to 85°C
LTC2057HVIDD#PBF
LTC2057HVIDD#TRPBF
LGDB
8-Lead Plastic DFN (3mm × 3mm)
–40°C to 85°C
LTC2057HDD#PBF
LTC2057HDD#TRPBF
LGCZ
8-Lead Plastic DFN (3mm × 3mm)
–40°C to 125°C
LTC2057HVHDD#PBF
LTC2057HVHDD#TRPBF
LGDB
8-Lead Plastic DFN (3mm × 3mm)
–40°C to 125°C
LTC2057IMS8#PBF
LTC2057IMS8#TRPBF
LTFGK
8-Lead Plastic MSOP
–40°C to 85°C
LTC2057HVIMS8#PBF
LTC2057HVIMS8#TRPBF
LTGDC
8-Lead Plastic MSOP
–40°C to 85°C
LTC2057HMS8#PBF
LTC2057HMS8#TRPBF
LTFGK
8-Lead Plastic MSOP
–40°C to 125°C
LTC2057HVHMS8#PBF
LTC2057HVHMS8#TRPBF
LTGDC
8-Lead Plastic MSOP
–40°C to 125°C
LTC2057IMS#PBF
LTC2057IMS#TRPBF
LTGCX
10-Lead Plastic MSOP
–40°C to 85°C
LTC2057HVIMS#PBF
LTC2057HVIMS#TRPBF
LTGCY
10-Lead Plastic MSOP
–40°C to 85°C
LTC2057HMS#PBF
LTC2057HMS#TRPBF
LTGCX
10-Lead Plastic MSOP
–40°C to 125°C
LTC2057HVHMS#PBF
LTC2057HVHMS#TRPBF
LTGCY
10-Lead Plastic MSOP
–40°C to 125°C
LTC2057IS8#PBF
LTC2057IS8#TRPBF
2057
8-Lead Plastic Small Outline
–40°C to 85°C
LTC2057HVIS8#PBF
LTC2057HVIS8#TRPBF
2057HV
8-Lead Plastic Small Outline
–40°C to 85°C
LTC2057HS8#PBF
LTC2057HS8#TRPBF
2057
8-Lead Plastic Small Outline
–40°C to 125°C
LTC2057HVHS8#PBF
LTC2057HVHS8#TRPBF
2057HV
8-Lead Plastic Small Outline
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
2057f
For more information www.linear.com/LTC2057
3
LTC2057/LTC2057HV
Electrical
Characteristics
(LTC2057/LTC2057HV) The l denotes the specifications which apply
over the full operating temperature range, otherwise specifications are at TA = 25°C. Unless otherwise noted, VS = ±2.5V; VCM = VOUT = 0V.
SYMBOL
VOS
∆VOS/∆T
IB
IOS
in
en
en P-P
CIN
CMRR
PSRR
AVOL
VOL – V–
V+ – VOH
ISC
SRRISE
SRFALL
GBW
fC
IS
VSDL
VSDH
ISD
ISDCOM
PARAMETER
CONDITIONS
Input Offset Voltage (Note 3)
Average Input Offset Voltage Drift (Note 3) –40°C to 125°C
Input Bias Current (Note 4)
–40°C to 85°C
–40°C to 125°C
Input Offset Current (Note 4)
–40°C to 85°C
–40°C to 125°C
Input Noise Current Spectral Density
1kHz
Input Noise Voltage Spectral Density
1kHz
Input Noise Voltage
DC to 10Hz
Differential Input Capacitance
Common Mode Input Capacitance
Common Mode Rejection Ratio (Note 5)
VCM = V– – 0.1V to V+ – 1.5V
–40°C to 125°C
Power Supply Rejection Ratio (Note 5)
VS = 4.75V to 36V
–40°C to 125°C
Open Loop Voltage Gain (Note 5)
VOUT = V – +0.2V to V+ –0.2V, RL =1kΩ
–40°C to 125°C
Output Voltage Swing Low
No Load
–40°C to 125°C
ISINK = 1mA
–40°C to 125°C
ISINK = 5mA
–40°C to 85°C
–40°C to 125°C
Output Voltage Swing High
No Load
–40°C to 125°C
ISOURCE = 1mA
–40°C to 125°C
ISOURCE = 5mA
–40°C to 85°C
–40°C to 125°C
Short Circuit Current
Rising Slew Rate
AV = –1, RL = 10kΩ
Falling Slew Rate
AV = –1, RL = 10kΩ
Gain Bandwidth Product
Internal Chopping Frequency
Supply Current
No Load
–40°C to 85°C
–40°C to 125°C
In Shutdown Mode
–40°C to 85°C
–40°C to 125°C
Shutdown Threshold (SD – SDCOM) Low –40°C to 125°C
Shutdown Threshold (SD – SDCOM) High –40°C to 125°C
SDCOM Voltage Range
–40°C to 125°C
SD Pin Current
–40°C to 125°C, VSD – VSDCOM = 0
SDCOM Pin Current
–40°C to 125°C, VSD – VSDCOM = 0
MIN
TYP
0.5
l
30
l
l
60
l
l
l
l
l
114
111
133
129
118
117
170
11
200
3
3
150
160
150
0.2
l
35
l
180
l
l
0.2
l
50
l
250
l
l
17
26
1.2
0.45
1.5
100
0.8
l
l
2.5
l
l
l
l
l
l
l
2
V–
–2
MAX
4
0.015
200
300
3.5
400
460
1.0
10
15
60
90
270
365
415
10
15
75
115
345
470
535
1.21
1.50
1.70
5.6
6.5
0.8
V+ –2V
–0.5
0.5
2
UNITS
μV
μV/°C
pA
pA
nA
pA
pA
nA
fA/√Hz
nV/√Hz
nVP-P
pF
pF
dB
dB
dB
dB
dB
dB
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mA
V/μs
V/μs
MHz
kHz
mA
mA
mA
μA
μA
μA
V
V
V
μA
μA
2057f
4
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Electrical
Characteristics
(LTC2057/LTC2057HV) The l denotes the specifications which apply
over the full operating temperature range, otherwise specifications are at TA = 25°C. Unless otherwise noted, VS = ±15V; VCM = VOUT = 0V.
SYMBOL
VOS
∆VOS/∆T
IB
IOS
in
en
en P-P
CIN
CMRR
PSRR
AVOL
VOL – V–
V+ – VOH
ISC
SRRISE
SRFALL
GBW
fC
IS
VSDL
VSDH
ISD
ISDCOM
PARAMETER
Input Offset Voltage (Note 3)
Average Input Offset Voltage Drift (Note 3)
Input Bias Current (Note 4)
Input Offset Current (Note 4)
Input Noise Current Spectral Density
Input Noise Voltage Spectral Density
Input Noise Voltage
Differential Input Capacitance
Common Mode Input Capacitance
Common Mode Rejection Ratio (Note 5)
CONDITIONS
–40°C to 125°C
l
–40°C to 85°C
–40°C to 125°C
l
l
–40°C to 85°C
–40°C to 125°C
1kHz
1kHz
DC to 10Hz
l
l
VCM = V– – 0.1V to V+ – 1.5V
–40°C to 125°C
VS = 4.75V to 36V
–40°C to 125°C
VOUT = V – +0.25V to V+ –0.25V, RL =10kΩ
–40°C to 125°C
No Load
–40°C to 125°C
ISINK = 1mA
–40°C to 125°C
ISINK = 5mA
–40°C to 85°C
–40°C to 125°C
No Load
–40°C to 125°C
ISOURCE = 1mA
–40°C to 125°C
ISOURCE = 5mA
–40°C to 85°C
–40°C to 125°C
Power Supply Rejection Ratio (Note 5)
Open Loop Voltage Gain (Note 5)
Output Voltage Swing Low
Output Voltage Swing High
Short Circuit Current
Rising Slew Rate
Falling Slew Rate
Gain Bandwidth Product
Internal Chopping Frequency
Supply Current
MIN
30
60
l
l
l
128
126
133
129
130
128
Shutdown Threshold (SD – SDCOM) Low
Shutdown Threshold (SD – SDCOM) High
SDCOM Voltage Range
SD Pin Current
SDCOM Pin Current
160
150
2
35
l
175
l
l
3
l
50
l
235
l
l
AV = –1, RL = 10kΩ
AV = –1, RL = 10kΩ
30
1.3
0.45
1.5
100
0.88
l
l
3
l
l
l
l
l
l
l
2
V–
–2.0
MAX
4.5
0.015
200
360
6.0
400
480
1.5
150
12
210
3
3
150
l
19
No Load
–40°C to 85°C
–40°C to 125°C
In Shutdown Mode
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C
–40°C to 125°C, VSD – VSDCOM = 0
–40°C to 125°C, VSD – VSDCOM = 0
TYP
0.5
12
45
60
100
255
360
435
15
45
75
125
335
465
560
1.35
1.65
1.83
8
9
0.8
V+ –2V
–0.5
0.5
2
UNITS
μV
μV/°C
pA
pA
nA
pA
pA
nA
fA/√Hz
nV/√Hz
nVP-P
pF
pF
dB
dB
dB
dB
dB
dB
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mA
V/μs
V/μs
MHz
kHz
mA
mA
mA
μA
μA
μA
V
V
V
µA
µA
2057f
For more information www.linear.com/LTC2057
5
LTC2057/LTC2057HV
Electrical
Characteristics
(LTC2057HV) The l denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C. Unless otherwise noted, VS = ±30V; VCM = VOUT = 0V.
SYMBOL
VOS
∆VOS/∆T
IB
VSDL
PARAMETER
CONDITIONS
Input Offset Voltage (Note 3)
Average Input Offset Voltage Drift (Note 3) –40°C to 125°C
Input Bias Current (Note 4)
–40°C to 85°C
–40°C to 125°C
Input Offset Current (Note 4)
–40°C to 85°C
–40°C to 125°C
Input Noise Current Spectral Density
1kHz
Input Noise Voltage Spectral Density
1kHz
Input Noise Voltage
DC to 10Hz
Differential Input Capacitance
Common Mode Input Capacitance
Common Mode Rejection Ratio (Note 5) VCM = V– – 0.1V to V+ – 1.5V
–40°C to 125°C
Power Supply Rejection Ratio (Note 5)
VS = 4.75V to 60V
–40°C to 125°C
Open Loop Voltage Gain (Note 5)
VOUT = V– +0.25V to V+ – 0.25V, RL = 10kΩ
–40°C to 125°C
Output Voltage Swing Low
No Load
–40°C to 125°C
ISINK = 1mA
–40°C to 125°C
ISINK = 5mA
–40°C to 85°C
–40°C to 125°C
Output Voltage Swing High
No Load
–40°C to 125°C
ISOURCE = 1mA
–40°C to 125°C
ISOURCE = 5mA
–40°C to 85°C
–40°C to 125°C
Short Circuit Current
Rising Slew Rate
AV = –1, RL = 10kΩ
Falling Slew Rate
AV = –1, RL = 10kΩ
Gain Bandwidth Product
Internal Chopping Frequency
Supply Current
No Load
–40°C to 85°C
–40°C to 125°C
In Shutdown Mode
–40°C to 85°C
–40°C to 125°C
Shutdown Threshold (SD – SDCOM) Low –40°C to 125°C
l
VSDH
Shutdown Threshold (SD – SDCOM) High –40°C to 125°C
l
2
SDCOM Voltage Range
–40°C to 125°C
l
V–
ISD
SD Pin Current
–40°C to 125°C, VSD – VSDCOM = 0
l
–2
ISDCOM
SDCOM Pin Current
–40°C to 125°C, VSD – VSDCOM = 0
l
IOS
in
en
en P-P
CIN
CMRR
PSRR
AVOL
VOL – V–
V+ – VOH
ISC
SRRISE
SRFALL
GBW
fC
IS
MIN
TYP
0.5
l
30
l
l
60
l
l
l
l
l
133
131
138
136
135
130
130
13
220
3
3
150
160
150
3
l
35
l
175
l
l
3
l
50
l
235
l
l
19
MAX
5
0.025
200
455
11
400
500
3
30
1.3
0.45
1.5
100
0.90
l
l
3
l
l
15
45
60
105
260
370
445
15
45
75
130
335
475
575
1.40
1.73
1.92
9
11
0.8
UNITS
μV
μV/°C
pA
pA
nA
pA
pA
nA
fA/√Hz
nV/√Hz
nVP-P
pF
pF
dB
dB
dB
dB
dB
dB
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mV
mA
V/μs
V/μs
MHz
kHz
mA
mA
mA
μA
μA
μA
V
V
V+ –2V
–0.5
0.5
V
µA
2
µA
2057f
6
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
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 LTC2057I/LTC2057HVI are guaranteed to meet specified
performance from –40°C to 85°C. The LTC2057H/LTC2057HVH are
guaranteed to meet specified performance from –40°C to 125°C.
Note 3: These parameters are guaranteed by design. Thermocouple effects
preclude measurements of these voltage levels during automated testing.
VOS is measured to a limit determined by test equipment capability.
Note 4: These specifications are limited by automated test system
capability. Leakage currents and thermocouple effects reduce test
accuracy. For tighter specifications, please contact LTC Marketing.
Note 5: Minimum specifications for these parameters are limited by
the capabilities of the automated test system, which has an accuracy of
approximately 10µV for VOS measurements. For reference, 10µV/60V is
136dB, 10µV/30V is 130dB, and 10µV/5V is 114dB.
2057f
For more information www.linear.com/LTC2057
7
LTC2057/LTC2057HV
Typical Performance Characteristics
Input Offset Voltage Distribution
160 TYPICAL UNITS
VS = ±2.5V
µ = –0.441 µV
σ = 0.452µV
30
25
20
15
10
25
20
15
10
0
–3 –2.5 –2 –1.5 –1 –0.5 0 0.5 1 1.5 2 2.5 3
VOS (µV)
NUMBER OF AMPLIFIERS
80
70
60
50
40
30
20
60
50
40
30
20
0
0
5
7
10
9 11 13 15 17 19
VOS TC (nV/°C)
2057 G03
90
70
60
50
40
30
20
1
3
5
7
0
9 11 13 15 17 19
VOS TC (nV/°C)
5
5
2
2
2
5 TYPICAL UNITS
4 VS = 30V
T = 25°C
3 A
VOS (µV)
1
0
–1
1
–1
–2
–2
–3
–3
–3
–4
–4
–4
1
2
VCM (V)
3
4
5
2057 G07
–5
0
5
10
9 11 13 15 17 19
VOS TC (nV/°C)
0
–2
0
7
5 TYPICAL UNITS
4 VS = 60V
T = 25°C
3 A
VOS (µV)
5 TYPICAL UNITS
4 VS = 5V
T = 25°C
3 A
–1
5
Input Offset Voltage vs
Input Common Mode Voltage
5
–5
3
2057 G06
Input Offset Voltage vs
Input Common Mode Voltage
–1
1
2057 G05
Input Offset Voltage vs
Input Common Mode Voltage
1
160 TYPICAL UNITS
VS = ±30V
TA = –40°C TO 125°C
µ = 1.32nV/°C
σ = 1.26nV/°C
80
10
2057 G04
0
–3 –2.5 –2 –1.5 –1 –0.5 0 0.5 1 1.5 2 2.5 3
VOS (µV)
Input Offset Voltage Drift
Distribution
160 TYPICAL UNITS
VS = ±15V
TA = –40°C TO 125°C
µ = 1.29nV/°C
σ = 1.14nV/°C
70
10
3
15
0
–3 –2.5 –2 –1.5 –1 –0.5 0 0.5 1 1.5 2 2.5 3
VOS (µV)
80
10
1
20
5
NUMBER OF AMPLIFIERS
160 TYPICAL UNITS
VS = ±2.5V
TA = –40°C TO 125°C
µ = 1.16nV/°C
σ = 0.97nV/°C
NUMBER OF AMPLIFIERS
90
25
Input Offset Voltage Drift
Distribution
Input Offset Voltage Drift
Distribution
160 TYPICAL UNITS
VS = ±30V
µ = –0.507 µV
σ = 0.548µV
30
2057 G02
2057 G01
VOS (µV)
35
5
5
0
Input Offset Voltage Distribution
160 TYPICAL UNITS
VS = ±15V
µ = –0.432 µV
σ = 0.525µV
30
NUMBER OF AMPLIFIERS
35
NUMBER OF AMPLIFIERS
35
NUMBER OF AMPLIFIERS
Input Offset Voltage Distribution
40
15
VCM (V)
20
25
30
2057 G08
–5
0
10
20
30
VCM (V)
40
50
60
2057 G09
2057f
8
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Typical Performance Characteristics
Input Offset Voltage
vs Supply Voltage
Long-Term Input Offset Voltage
Drift
5
100
40 TYPICAL UNITS
4 VS = ±2.5V
3
2
1
1
0
–1
0
–2
–3
–3
–4
–4
–5
0.1
100
10
TIME (HOURS)
1
1000
2057 G09
0.01
–50 –25
2057 G12
Input Bias Current vs Input
Common Mode Voltage
Input Bias Current
vs Supply Voltage
50
VS = 5V
40 TA = 25°C
50
VS = 30V, 60V
40 TA = 25°C
20
10
10
IB (pA)
20
0
–10
IB (+IN)
–20
IB (–IN), VS = 60V
30
IB (–IN)
VCM = VS /2
40 TA = 25°C
30
IB (–IN), VS = 30V
0
IB (+IN), VS = 30V
–10
IB (+IN), VS = 60V
–20
10
0
–10
–30
–30
–40
–40
–40
–50
–50
1
1.5
2
2.5
3
VCM (V)
3.5
4
20
30
VCM (V)
40
50
60
–50
VS = ±2.5V
2057 G16
0
10
20
2057 G14
DC to 10Hz Voltage Noise
INPUT-REFFERED VOLTAGE NOISE (100nV/DIV)
INPUT-REFFERED VOLTAGE NOISE (100nV/DIV)
10
2057 G13
DC to 10Hz Voltage Noise
TIME (1s/DIV)
0
40
30
VS (V)
50
60
70
2057 G15
Input Voltage Noise Spectrum
35
VS = ±30V
30
INPUT-REFERRED VOLTAGE
NOISE DENSITY (nV/√Hz)
0.5
IB (+IN)
–20
–30
0
IB (–IN)
20
IB (pA)
50
30
25 50 75 100 125 150
TEMPERATURE (°C)
0
2057 G10
Input Bias Current vs Input
Common Mode Voltage
IB (pA)
1
–1
–2
0 5 10 15 20 25 30 35 40 45 50 55 60 65
VS (V)
VCM = 0V
VS = ±2.5V
VS = ±15V
VS = ±30V
10
IB (nA)
2
VOS (µV)
VOS (µV)
5 TYPICAL UNITS
4 VCM = VS /2
T = 25°C
3 A
–5
Input Bias Current vs Temperature
5
AV = +11
VS = ±2.5V
VS = ±30V
25
20
15
10
5
TIME (1s/DIV)
2057 G17
0
0.1
1
10 100 1k 10k 100k
FREQUENCY (Hz)
1M
2057 G18
2057f
For more information www.linear.com/LTC2057
9
LTC2057/LTC2057HV
Typical Performance Characteristics
Common Mode Rejection Ratio
vs Frequency
Input Current Noise Spectrum
120
AV = +11
VS = ±2.5V
VS = ±30V
0.20
VS = 30V
VCM = VS /2
100
80
0.15
CMRR (dB)
INPUT-REFERRED CURRENT
NOISE DENSITY (pA/√Hz)
0.25
0.10
60
40
0.05
0
20
0.1
1
10
100
FREQUENCY (Hz)
1k
0
100
10k
1000
1k
10k
FREQUENCY (Hz)
100k
2057 G19
2057 G20
Power Supply Rejection Ratio
vs Frequency
120
Closed Loop Gain vs Frequency
50
VS = 30V
VCM = VS /2
80
PSRR (dB)
+PSRR
60
40
–PSRR
20
0
VS = ±15V
RL = 10kΩ
AV = +100
40
CLOSED LOOP GAIN (dB)
100
30
AV = +10
20
10
0
–10
AV = +1
–20
–20
100
1k
10k
100k
FREQUENCY (Hz)
1M
–30
10M
AV = –1
1k
10k
100k
1M
FREQUENCY (Hz)
2057 G21
10M
2057 G22
Gain/Phase vs Frequency
Gain/Phase vs Frequency
80
70
120
70
90
60
50
60
50
60
40
30
40
30
30
0
PHASE
–30
10
–60
0
–90
–10
–20
–30
VS = ±2.5V
RL = 1kΩ
CL = 50pF
CL = 200pF
–40
10k
1M
100k
FREQUENCY (Hz)
10M
2057 G23
150
120
PHASE
30
90
0
GAIN
20
–30
–60
10
PHASE (dB)
GAIN
20
GAIN (dB)
150
PHASE (dB)
80
60
GAIN (dB)
1M
–90
0
VS = ±30V
RL = 1kΩ
CL = 50pF
CL = 200pF
–120
–10
–150
–20
–180
–30
–210
–40
10k
1M
100k
FREQUENCY (Hz)
–120
–150
–180
10M
–210
2057 G24
2057f
10
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Typical Performance Characteristics
VS = ±2.5V, AV = +1
SD – SDCOM
ISS
VIN
VOUT
3
2
1
0
0.3
0.2
0.1
0
–0.1
–10
10
0
20
30
TIME (µs)
SD – SDCOM
ISS
VIN
VOUT
2
1
0
0.4
0.3
0.2
0.1
0
–0.1
–0.2
50
40
VS = ±30V, AV = +1
3
–10
10
0
20
30
TIME (µs)
2057 G26
Start-Up Transient
with Sinusoid Input
2
1
SD – SDCOM 0.4
ISS
0.3
VIN
VOUT
0.2
0
0.1
0.1
–0.1
VS = ±2.5V
AV = +1
10
–0.2
20 30 40
TIME (µs)
50
60
4
3
2
1
0
0.4
0.3
SD – SDCOM
ISS
VIN
VOUT
0.2
0.1
0
–0.3
70
–10
0
10
–0.1
VS = ±30V
–0.2
AV = +1
–0.3
50 60 70
20 30 40
TIME (µs)
2057 G27
Closed Loop Output Impedance
vs Frequency
Closed Loop Output Impedance
vs Frequency
1000
VS = ±2.5V
THD+N vs Amplitude
0.1
VS = ±30V
100
100
AV = +100
10
ZOUT (Ω)
ZOUT (Ω)
2057 G28
AV = +10
1
0.01
10
THD+N (%)
1000
AV = +100
AV = +10
1
0.001
AV = +1
0.1
0.01
100
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
SD – SDCOM (V)
SUPPLY CURRENT (mA)
4
3
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
SD – SDCOM (V)
SUPPLY CURRENT (mA)
Start-Up Transient
with Sinusoid Input
0
–0.2
50
40
2057 G25
–10
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
0.4
4
SD – SDCOM (V)
SUPPLY CURRENT (mA)
4
Shutdown Transient
with Sinusoid Input
INPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
SD – SDCOM (V)
SUPPLY CURRENT (mA)
Shutdown Transient
with Sinusoid Input
1k
10k
100k
FREQUENCY (Hz)
AV = +1
0.1
1M
10M
2057 G29
0.01
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
2057 G30
fIN = 1kHz
VS = ±15V
AV = +1
RL = 10kΩ
BW = 80kHz
0.0001
0.01
1
0.1
OUTPUT AMPLITUDE (VRMS)
10
2057 G31
2057f
For more information www.linear.com/LTC2057
11
LTC2057/LTC2057HV
Typical Performance Characteristics
THD+N vs Frequency
Supply Current vs Supply Voltage
IS (mA)
25°C
0.8
–40°C
0.6
–55°C
0.2
0.2
2057 G32
1.4
8
150°C
5
125°C
4
3
85°C
25°C
2
–55°C
1
0
IS (mA)
IS (µA)
6
0
VS = ±2.5V
SDCOM = –2.5V
1.2
7
85°C
0.8
25°C
0
SHUTDOWN PIN CURRENT (µA)
SHUTDOWN PIN CURRENT (µA)
0
ISD –50°C
ISDCOM –50°C
ISD 125°C
ISDCOM 125°C
–3
–4
–5
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
SD – SDCOM (V)
SD = SDCOM = VS /2
0.8
–1
2057 G38
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
SD – SDCOM (V)
2057 G37
No Phase Reversal
20
ISDCOM 150°C
0.6
ISDCOM 25°C
0.4
ISDCOM –55°C
0.2
0
–0.2
ISD –55°C
–0.4
ISD 25°C
–0.6
ISD 150°C
–1.0
0
10
5
0
–5
–15
5 10 15 20 25 30 35 40 45 50 55 60
VS (V)
VIN
VOUT
15
–10
–0.8
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
SD – SDCOM (V)
–55°C
0.2
1.0
1
–40°C
0.4
Shutdown Pin Current
vs Supply Voltage
2
25°C
0.8
2057 G36
VS = ±30V
SDCOM = 0V
150
85°C
0.6
–55°C
0.2
–40°C
3
120
150°C
125°C
1.0
–40°C
0.6
VS = ±30V
SDCOM = 0V
1.2
0.4
5 10 15 20 25 30 35 40 45 50 55 60
VS (V)
–2
1.4
150°C
125°C
1.0
Shutdown Pin Current
vs Shutdown Pin Voltage
4
0
30
60
90
TEMPERATURE (°C)
Supply Current vs Shutdown
Control Voltage
1.6
2057 G35
5
–30
2057 G34
Supply Current vs Shutdown
Control Voltage
SD = SDCOM = VS/2
9
0
–60
5 10 15 20 25 30 35 40 45 50 55 60
VS (V)
2057 G33
Shutdown Supply Current
vs Supply Voltage
10
±15V
0.6
0.4
0
±2.5V
0.8
0.4
0
10000
±30V
1.0
IS (mA)
1000
100
FREQUENCY (Hz)
1.2
85°C
1.0
THD+N (%)
10
150°C
125°C
1.2
0.001
0.0001
1.4
IS (mA)
VOUT = 2VRMS
VS = ±15V
AV = +1
RL = 10kΩ
BW = 80kHz
0.01
Supply Current vs Temperature
1.4
VOLTAGE (V)
0.1
–20
AV = +1
VS = ±15V
VIN = ±16V
RIN = 1kΩ
0.2mS/DIV
2057 G40
2057 G39
2057f
12
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Typical Performance Characteristics
Output Voltage Swing High
vs Load Current
100
VS = ±2.5V
150°C
25°C
0.1
0.01
0.1
1
ISOURCE (mA)
10
VS = ±2.5V
100
85°C
125°C
150°C
10m
25°C
0.01
0.1
1
ISINK (mA)
10
10
–40°C
0.1
25°C
0.01
0.1
1
ISINK (mA)
10
100
ISC (mA)
SINKING
30
60
10
100
2057 G46
VS = ±30V
SINKING
30
10
10
0
–50 –25
0
SOURCING
40
SOURCING
10
2057 G47
0.1
1
ISINK (mA)
50
20
25 50 75 100 125 150
TEMPERATURE (°C)
0.01
Short-Circuit Current
vs Temperature
20
0
25°C
–40°C
2057 G45
20
0
–50 –25
150°C
125°C
85°C
0.1m
0.001
VS = ±15V
40
SOURCING
2057 G43
VS = ±30V
1m
50
40
100
Output Voltage Swing Low
vs Load Current
Short-Circuit Current
vs Temperature
50
10
10m
2057 G44
60
0.1
1
ISOURCE (mA)
1
150°C
125°C
85°C
0.1m
0.001
VS = ±2.5V
0.01
10
0.1
Short-Circuit Current
vs Temperature
25°C
–40°C
2057 G42
10m
100
85°C
0.1m
0.001
100
100
1m
0.1m
0.001
ISC (mA)
1
ISOURCE (mA)
VS = ±15V
1
1m
30
0.1
10
–40°C
0.1
125°C
1m
Output Voltage Swing Low
vs Load Current
VOL – V – (V)
VOL – V – (V)
1
0.01
2057 G41
Output Voltage Swing Low
vs Load Current
25°C
–40°C
0.1m
0.001
100
150°C
0.1
10m
1m
0.1m
0.001
60
150°C
125°C
10m
1m
10
85°C
1
V+ – VOH (V)
–40°C
10m
1
V+ – VOH (V)
V+ – VOH (V)
85°C
VS = ±30V
10
10
125°C
0.1
100
VS = ±15V
VOL – V – (V)
1
Output Voltage Swing High
vs Load Current
ISC (mA)
10
Output Voltage Swing High
vs Load Current
25 50 75 100 125 150
TEMPERATURE (°C)
2057 G48
SINKING
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
2057 G49
2057f
For more information www.linear.com/LTC2057
13
LTC2057/LTC2057HV
Typical Performance Characteristics
Large Signal Response
Large Signal Response
0.6
6
VS = ±2.5V
VIN = ±0.5V
AV = +1
CL = 200pF
0.4
8
6
4
VOUT (V)
0
0
–0.2
–2
–0.4
–4
VS = ±30V
VIN = ±10V
AV = +1
CL = 200pF
10
2
VOUT (V)
VOUT (V)
VS = ±15V
VIN = ±5V
AV = +1
CL = 200pF
4
0.2
Large Signal Response
12
2
0
–2
–4
–6
–8
–10
–0.6
–4 –2
0
2
4 6 8
TIME (µs)
–6
–10
10 12 14 16
0
10
20
30 40 50
TIME (µs)
60
70
2057 G50
Small Signal Response
Small Signal Response
50
50
CL = 200pF
10
–10
–30
VS = ±2.5V
VIN = ±50mV
AV = +1
–2
–1
0
1
5
6
–70
7
–2
–1
0
1
2
3
4
TIME (µs)
5
40
VS = ±2.5V
VIN = 100mV
AV = +1
35
–70
7
+OS
15
10
40
VS = ±15V
VIN = 100mV
AV = +1
35
–OS
25
20
15
+OS
100
CL (pF)
1000
2057 G56
1
2
3
4
TIME (µs)
0
5
6
7
VS = ±30V
VIN = 100mV
AV = +1
25
20
15
+OS
10
–OS
5
10
0
30
10
5
–1
Small Signal Overshoot
vs Load Capacitance
OVERSHOOT (%)
20
–2
2057 G55
30
OVERSHOOT (%)
OVERSHOOT (%)
30
0
6
Small Signal Overshoot
vs Load Capacitance
25
VS = ±30V
VIN = ±50mV
AV = +1
2057 G54
Small Signal Overshoot
vs Load Capacitance
35
–10
–50
2057 G53
40
10
–30
VS = ±15V
VIN = ±50mV
AV = +1
–50
2
3
4
TIME (µs)
CL = 200pF
30
VOUT (mV)
VOUT (mV)
VOUT (mV)
–30
–50
60 80 100 120 140 160
TIME (µs)
Small Signal Response
30
–10
40
70
50
CL = 200pF
10
20
2057 G52
70
30
0
2057 G51
70
–70
–12
–20
80
–OS
5
10
100
CL (pF)
1000
2057 G57
0
10
100
CL (pF)
1000
2057 G58
2057f
14
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Typical Performance Characteristics
Large Signal Settling Transient
VIN (V)
VIN (V)
Large Signal Settling Transient
2
1
0
2
1
0
12
8
6
VIN
4
VOUT
VOUT(AVG) 2
VOUT (mV)
6
VIN
4
VOUT
VOUT(AVG) 2
8
0
0
–2
–2
–5 0 5 10 15 20 25 30 35 40 45 50 55 60
TIME (µs)
–4
–5 0 5 10 15 20 25 30 35 40 45 50 55 60
TIME (µs)
2057 G59
VS = ±2.5V
AV = –100
RF = 10kΩ
CL = 100pF
–0.5
Output Overload Recovery
1
0
VIN (V)
VIN (V)
VIN (V)
VIN
0
2057 G60
Output Overload Recovery
Output Overload Recovery
0.5
VIN
–1
–5
0
5
0
–5
–3
–10
–6
–15
VS = ±15V
AV = –100 –12
RF = 10kΩ
CL = 100pF –15
–18
10 15 20 25 30 35 40 45
TIME (µs)
VS = ±30V
AV = –100
RF = 10kΩ
CL = 100pF
–10 0
Output Overload Recovery
1
0
VIN (V)
VIN (V)
VIN
VIN
–1
–30
2057 G63
Output Overload Recovery
Output Overload Recovery
–25
–35
10 20 30 40 50 60 70 80 90
TIME (µs)
2057 G62
0.5
–20
VOUT (V)
VOUT (V)
–1
2057 G61
VIN (V)
VIN
0
–9
–3
10 20 30 40 50 60 70 80
TIME (µs)
0
0
–2
VOUT (V)
0
–2
–20 –10 0
2
VOUT
VOUT
VOUT
VOUT (mV)
AV = –1
RF = 10k
VS = ±15V
10
AV = –1
RF = 10k
VS = ±15V
10
2
0
VIN
–2
–0.5
30
15
3
0
–1
10 20 30 40 50 60 70 80
TIME (µs)
2057 G64
VS = ±15V
AV = –100
RF = 10kΩ
CL = 100pF
6
VOUT
3
0
–3
–10 0 10 20 30 40 50 60 70 80 90 100
TIME (µs)
2057 G65
20
VOUT
15
10
VS = ±30V
AV = –100
RF = 10kΩ
CL = 100pF
–20
0
20
VOUT (V)
–10 0
1
VOUT
9
VOUT (V)
VS = ±2.5V
AV = –100
RF = 10kΩ
CL = 100pF
VOUT (V)
2
25
12
5
0
40 60 80
TIME (µs)
–5
100 120 140
2057 G66
2057f
For more information www.linear.com/LTC2057
15
LTC2057/LTC2057HV
Pin Functions
MS8 and S8/DD8
SD (Pin 1/Pin 1): Shutdown Control Pin.
SDCOM (Pin 8/Pin 8): Reference Voltage for SD.
–IN (Pin 2/Pin 2): Inverting Input.
V+ (Pin 7/Pin 7): Positive Power Supply.
+IN (Pin 3/Pin 3): Non-Inverting Input.
OUT (Pin 6/Pin 6): Amplifier Output
V– (Pin 4/Pin 4, 9): Negative Power Supply.
NC (Pin 5/Pin 5): No Internal Connection.
MS10
GRD (Pin 1): Guard Ring. No Internal Connection.
SD (Pin 10): Shutdown Control Pin.
–IN (Pin 2): Inverting Input.
SDCOM (Pin 9): Reference Voltage for SD.
+IN (Pin 3): Non-Inverting Input.
V+ (Pin 8): Positive Power Supply.
GRD (Pin 4): Guard Ring. No Internal Connection.
NC (Pin 7): No Internal Connection.
V– (Pin 5): Negative Power Supply.
OUT (Pin 6): Amplifier Output.
2057f
16
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Block Diagrams
Amplifier
V+
525Ω
–IN
V+
V+
–
V–
V
OUT
+
+
525Ω
+IN
V–
V–
2057 BD1
V–
Shutdown Circuit
V+
V+
0.5µA
10k
SD
–
V+
V–
5.25V
VTH ≈ 1.4V
10k
SDCOM
–+
SD
+
0.5µA
V–
2057 BD2
V–
2057f
For more information www.linear.com/LTC2057
17
LTC2057/LTC2057HV
Applications Information
Input Voltage Noise
Chopper stabilized amplifiers like the LTC2057 achieve low
offset and 1/f noise by heterodyning DC and flicker noise
to higher frequencies. In a classical chopper stabilized
amplifier, this process results in idle tones at the chopping
frequency and its odd harmonics.
The LTC2057 utilizes circuitry to suppress these spurious
artifacts to well below the offset voltage. The typical ripple
magnitude at 100kHz is much less than 1µVRMS.
The voltage noise spectrum of the LTC2057 is shown in
Figure 1. If lower noise is required, consider one of the
following circuits from the Typical Applications section:
"DC Stabilized, Ultralow Noise Amplifier" or "Paralleling
Choppers to Improve Noise."
30
AV = +11
VS = ±2.5V
AV = +11
VS = ±2.5
NO 1/f NOISE
0.20
0.15
0.01
0.05
0
0.1
10
100
FREQUENCY (Hz)
1
1k
10k
2057 F02
Figure 2. Input Current Noise Spectrum
It is important to note that the current noise is not equal
to 2qIB. This formula is relevant for base current in bipolar
transistors and diode currents, but for most chopper and
auto-zero amplifiers with switched inputs, the dominant
current noise mechanism is not shot noise.
25
Input Bias Current
20
15
As illustrated in Figure 3, the LTC2057’s input bias current
originates from two distinct mechanisms. Below 75°C,
input bias current is nearly constant with temperature,
and is caused by charge injection from the clocked input
switches used in offset correction.
NO 1/f NOISE
10
5
0
0.1
1
10 100 1k 10k 100k
FREQUENCY (Hz)
1M
100
2057 F01
For applications with high source impedances, input current noise can be a significant contributor to total output
noise. For this reason, it is important to consider noise
current interaction with circuit elements placed at an
amplifier’s inputs.
The current noise spectrum of the LTC2057 is shown in
Figure 2. The characteristic curve shows no 1/f behavior.
As with all zero-drift amplifiers, there is a significant current noise component at the offset-nulling frequency. This
phenomenon is discussed in the Input Bias Current section.
IB (nA)
Input Current Noise
10
1
LEAKAGE CURRENT
Figure 1. Input Voltage Noise Spectrum
1 TYPICAL UNIT
VS = ±2.5V
INJECTION CURRENT
INPUT VOLTAGE NOISE DENSITY (nV/√Hz)
35
INPUT CURRENT NOISE DENSITY (pA/√Hz)
0.25
25°C MAX IB SPEC
0.1
0.01
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
2057 F03
Figure 3. Input Bias Current vs Temperature
2057f
18
For more information www.linear.com/LTC2057
LTC2057/LTC2057HV
Applications Information
For zero-drift amplifiers, clock feed-through will be
proportional to source impedance and the magnitude of
injection current, a measure of which is IB at 25°C. In
order to minimize clock feed-through, keep gain-setting
resistors and source impedances as low as possible. If
high impedances are required, place a capacitor across
the feedback resistor to limit the bandwidth of the closed
loop gain. Doing so will effectively filter out the clock
feed-through signal.
Injection currents from the two inputs are of equal magnitude but opposite direction. Therefore, input bias current
effects due to injection currents will not be canceled by
placing matched impedances at both inputs.
MICROVOLTS REFERRED TO 25°C
Above 75°C, leakage of the ESD protection diodes begins to
dominate the input bias current and continues to increase
exponentially at elevated temperatures. Unlike injection
current, leakage currents are in the same direction for both
inputs. Therefore, the output error due to leakage currents
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.800
0.600
0.400
0.200
0
25
30
35
40
45
TEMPERATURE (°C)
2057 F04
can be mitigated by matching the source impedances seen
by the two inputs.
Thermocouple Effects
In order to achieve accuracy on the microvolt level, thermocouple effects must be considered. Any connection
of dissimilar metals forms a thermoelectric junction and
generates a small temperature-dependent voltage. Also
known as the Seebeck Effect, these thermal EMFs can be
the dominant error source in low-drift circuits.
Connectors, switches, relay contacts, sockets, resistors,
and solder are all candidates for significant thermal EMF
generation. Even junctions of copper wire from different
manufacturers can generate thermal EMFs of 200nV/°C,
which is over 13 times the maximum drift specification of
the LTC2057. Figures 4 and 5 illustrate the potential magnitude of these voltages and their sensitivity to temperature.
In order to minimize thermocouple-induced errors, attention must be 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 and avoid connectors, sockets, switches, and relays whenever possible.
If such components are required, they should be selected
for low thermal EMF characteristics. Furthermore, the
number, type, and layout of junctions should be matched
for both inputs with respect to thermal gradients on the
circuit board. Doing so may involve deliberately introducing
dummy junctions to offset unavoidable junctions.
THERMALLY PRODUCED VOLTAGE IN MICROVOLTS
The DC average of injection current is the specified input
bias current, but this current has a frequency component
at the chopping frequency as well. When these small
current pulses, typically about 0.7nARMS, interact with
source impedances or gain setting resistors, the resulting
voltage spikes are amplified by the closed loop gain. For
high impedances, this may cause the 100kHz chopping
frequency to be visible in the output spectrum, which is
a phenomenon known as clock feed-through.
100
SLOPE ≈ 1.5µV/°C
BELOW 25°C
50
0
64% SN/36% Pb
60% Cd/40% SN
SLOPE ≈ 160nV/°C
BELOW 25°C
–50
–100
10
30
0
40
50
20
SOLDER-COPPER JUNCTION DIFFERENTIAL TEMPERATURE
SOURCE: NEW ELECTRONICS 02-06-77
2057 F05
Figure 4. Thermal EMF Generated by Two Copper Wires
From Different Manufacturers
Figure 5. Solder-Copper Thermal EMFs
2057f
For more information www.linear.com/LTC2057
19
LTC2057/LTC2057HV
Applications Information
RF §
HEAT SOURCE/
POWER DISSIPATOR
#
RELAY
**
VTHERMAL
–+
THERMAL
GRADIENT
RG
VTHERMAL
VIN
–IN
†
‡
MATCHING RELAY
*
RL§
+IN
** RG
–+
LTC2057
RF
NC
* CUT SLOTS IN PCB FOR THERMAL ISOLATION.
** INTRODUCE DUMMY JUNCTIONS AND COMPONENTS TO OFFSET UNAVOIDABLE JUNCTIONS OR CANCEL THERMAL EMFs.
† ALIGN INPUTS SYMMETRICALLY WITH RESPECT TO THERMAL GRADIENTS.
‡ INTRODUCE DUMMY TRACES AND COMPONENTS FOR SYMMETRICAL THERMAL HEAT SINKING.
§ LOADS AND FEEDBACK CAN DISSIPATE POWER AND GENERATE THERMAL GRADIENTS. BE AWARE OF THEIR THERMAL EFFECTS.
# COVER CIRCUIT TO PREVENT AIR CURRENTS FROM CREATING THERMAL GRADIENTS.
2057 F06
Figure 6. Techniques for Minimizing Thermocouple-Induced Errors
LEAKAGE
CURRENT
GRD
RG**
VBIAS
SD
SDCOM
V+
+IN
*
HIGH-Z
SENSOR
LTC2057
MS10
–IN
GRD
NC
V–
GUARD
RING
NO SOLDER MASK
OVER GUARD RING
V+
OUT
V–
VOUT
RF
* NO LEAKAGE CURRENT. V+IN = VGRD
** VERROR = ILEAK • RG; RG
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