2002-06-13
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73-381-48 OPA277UA prec op-amp SO8
73-382-21 OPA2277UA op-amp SO8
73-387-59 OPA277PA op-amp DIL8
73-388-90 OPA4277PA op-amp DIL14
OPA277
OPA2277
OPA4277
®
OPA
OPA
277
227
OPA
7
4277
OPA
2277
OPA
277
OPA
4277
For most current data sheet and other product
information, visit www.burr-brown.com
High Precision
OPERATIONAL AMPLIFIERS
FEATURES
DESCRIPTION
● ULTRA LOW OFFSET VOLTAGE: 10µV
● ULTRA LOW DRIFT: ±0.1µV/°C
● HIGH OPEN-LOOP GAIN: 134dB
● HIGH COMMON-MODE REJECTION: 140dB
● HIGH POWER SUPPLY REJECTION: 130dB
● LOW BIAS CURRENT: 1nA max
● WIDE SUPPLY RANGE: ±2V to ±18V
● LOW QUIESCENT CURRENT: 800µA/amp
● SINGLE, DUAL, AND QUAD VERSIONS
● REPLACES OP-07, OP-77, OP-177
The OPA277 series precision op amps replace the industry
standard OP-177. They offer improved noise, wider output
voltage swing, and are twice as fast with half the quiescent
current. Features include ultra low offset voltage and drift, low
bias current, high common-mode rejection, and high power
supply rejection. Single, dual, and quad versions have identical
specifications for maximum design flexibility.
OPA277 series op amps operate from ±2V to ±18V supplies
with excellent performance. Unlike most op amps which
are specified at only one supply voltage, the OPA277 series
is specified for real-world applications; a single limit applies over the ±5V to ±15V supply range. High performance
is maintained as the amplifiers swing to their specified limits.
Because the initial offset voltage (±20µV max) is so low, user
adjustment is usually not required. However, the single version
(OPA277) provides external trim pins for special applications.
OPA277 op amps are easy to use and free from phase inversion
and overload problems found in some other op amps. They are
stable in unity gain and provide excellent dynamic behavior
over a wide range of load conditions. Dual and quad versions
feature completely independent circuitry for lowest crosstalk
and freedom from interaction, even when overdriven or overloaded.
Single (OPA277) and dual (OPA2277) versions are available
in 8-pin DIP and SO-8 surface-mount packages. The quad
(OPA4277) comes in 14-pin DIP and SO-14 surface-mount
packages. All are fully specified from –40°C to +85°C and
operate from –55°C to +125°C.
APPLICATIONS
●
●
●
●
●
●
●
TRANSDUCER AMPLIFIER
BRIDGE AMPLIFIER
TEMPERATURE MEASUREMENTS
STRAIN GAGE AMPLIFIER
PRECISION INTEGRATOR
BATTERY POWERED INSTRUMENTS
TEST EQUIPMENT
OPA277
Offset Trim
1
8
Offset Trim
–In
2
7
V+
+In
3
6
Output
V–
4
5
NC
OPA4277
OPA2277
Out A
1
14
Out D
–In A
2
13
–In D
A
8-Pin DIP, SO-8
Out A
–In A
1
2
+In A
3
V–
4
8
A
7
B
V+
Out B
6
–In B
5
+In B
8-Pin DIP, SO-8
D
+In A
3
12
+In D
V+
4
11
V–
+In B
5
10
+In C
B
C
–In B
6
9
–In C
Out B
7
8
Out C
14-Pin DIP, SO-14
IInternational Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111
Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
© 1997 Burr-Brown Corporation
SBOS079
PDS-1413D
Printed in U.S.A. March, 1999
SPECIFICATIONS: VS = ±5V to VS = ±15V
At TA = +25°C, and RL = 2kΩ, unless otherwise noted.
Boldface limits apply over the specified temperature range, –40°C to +85°C.
OPA277PA, UA
OPA2277PA, UA
OPA4277PA, UA
OPA277P, U
OPA2277P, U
PARAMETER
CONDITION
OFFSET VOLTAGE
Input Offset Voltage:
OPA277P, U (high grade, single)
OPA2277P, U (high grade, dual)
All PA, UA Versions
MIN
VOS
Input Offset Voltage Over Temperature
OPA277P, U (high grade, single)
OPA2277P, U (high grade, dual)
All PA, UA Versions
TA = –40°C to +85°C
TA = –40°C to +85°C
TA = –40°C to +85°C
Input Offset Voltage Drift
dVOS/dT
OPA277P, U (high grade, single)
OPA2277P, U (high grade, dual)
All PA, UA Versions
TA = –40°C to +85°C
TA = –40°C to +85°C
TA = –40°C to +85°C
Input Offset Voltage: (all models)
vs Time
vs Power Supply
TA = –40°C to +85°C
Channel Separation (dual, quad)
INPUT BIAS CURRENT
Input Bias Current
TA = –40°C to +85°C
Input Offset Current
TA = –40°C to +85°C
MAX
±10
±10
±20
±25
±0.1
±0.1
0.2
±0.3
±0.5
I OS
±0.5
Input Voltage Noise Density, f = 10Hz en
f = 100Hz
f = 1kHz
f = 10kHz
Current Noise Density, f = 1kHz
in
0.22
0.035
12
8
8
8
0.2
NOISE
Input Voltage Noise, f = 0.1 to 10Hz
VCM
CMRR
INPUT IMPEDANCE
Differential
Common-Mode
OPEN-LOOP GAIN
Open-Loop Voltage Gain
TA = –40°C to +85°C
FREQUENCY RESPONSE
Gain-Bandwidth Product
GBW
Slew Rate
SR
Settling Time, 0.1%
0.01%
Overload Recovery Time
Total Harmonic Distortion + Noise THD+N
OUTPUT
Voltage Output
TA = –40°C to +85°C
TA = –40°C to +85°C
Short-Circuit Current
Capacitive Load Drive
VCM = (V–) +2V to (V+) –2V
VCM = (V–) +2V to (V+) –2V
(V–) +2
130
128
VO = (V–)+0.5V to (V+)–1.2V, RL = 10kΩ
VO = (V–)+0.5V to (V+)–1.5V, RL = 2kΩ
VO = (V–)+0.5V to (V+)–1.5V, RL = 2kΩ
126
126
±0.15
✻
✻
±0.5
±0.5
RL = 10kΩ
RL = 10kΩ
RL = 2kΩ
RL = 2kΩ
(V–)
(V–)
(V–)
(V–)
+0.5
+0.5
+1.5
+1.5
±1
✻
±1
✻
±2
±2
UNITS
±50
µV
µV
µV
±100
µV
µV
µV
±1
µV/°C
µV/°C
µV/°C
±1
±1
µV/mo
µV/V
µV/V
µV/V
±2.8
±4
±2.8
±4
nA
nA
nA
nA
µVp-p
µVrms
nV/√Hz
nV/√Hz
nV/√Hz
nV/√Hz
pA/√Hz
✻
✻
✻
✻
✻
✻
✻
(V+) –2
140
140
134
✻
115
115
✻
✻
(V+)
(V+)
(V+)
(V+)
±35
See Typical Curve
I SC
CLOAD
MAX
✻
1
0.8
14
16
3
0.002
VS = ±15V, G = 1, 10V Step
VS = ±15V, G = 1, 10V Step
VIN • G = VS
1kHz, G = 1, VO = 3.5Vrms
VO
±0.15
±0.25
100 || 3
250 || 3
VCM = (V–) +2V to (V+) –2V
AOL
TYP(1)
±20
0.1
IB
INPUT VOLTAGE RANGE
Common-Mode Voltage Range
Common-Mode Rejection
TA = –40°C to +85°C
MIN
±30
±50
VS = ±2V to ±18V
VS = ±2V to ±18V
dc
PSRR
TYP(1)
–1.2
–1.2
–1.5
–1.5
✻
✻
V
dB
dB
✻
✻
MΩ || pF
GΩ || pF
✻
✻
dB
dB
dB
✻
✻
✻
✻
✻
✻
MHz
V/µs
µs
µs
µs
%
✻
✻
✻
✻
✻
✻
✻
✻
✻
✻
V
V
V
V
mA
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
®
OPA277, 2277, 4277
2
SPECIFICATIONS: VS = ±5V to VS = ±15V
(CONT)
At TA = +25°C, and RL = 2kΩ, unless otherwise noted.
Boldface limits apply over the specified temperature range, –40°C to +85°C.
OPA277PA, UA
OPA2277PA, UA
OPA4277PA, UA
OPA277P, U
OPA2277P, U
PARAMETER
CONDITION
POWER SUPPLY
Specified Voltage Range
Operating Voltage Range
Quiescent Current (per amplifier)
TA = –40°C to +85°C
MIN
±5
±2
VS
±790
IO = 0
IO = 0
IQ
TEMPERATURE RANGE
Specified Range
Operating Range
Storage Range
Thermal Resistance
SO-8 Surface-Mount
8-Pin DIP
14-Pin DIP
SO-14 Surface-Mount
TYP(1)
–40
–55
–55
MAX
MIN
±15
±18
±825
±900
✻
✻
85
125
125
✻
✻
✻
TYP(1)
✻
θJA
✻
✻
✻
✻
150
100
80
100
MAX
UNITS
✻
✻
✻
✻
V
V
µA
µA
✻
✻
✻
°C
°C
°C
°C/W
°C/W
°C/W
°C/W
✻ Specifications same as OPA277P, U.
NOTE: (1) VS = ±15V.
ABSOLUTE MAXIMUM RATINGS(1)
ELECTROSTATIC
DISCHARGE SENSITIVITY
Supply Voltage .................................................................................... 36V
Input Voltage ..................................................... (V–) –0.7V to (V+) +0.7V
Output Short-Circuit(2) .............................................................. Continuous
Operating Temperature .................................................. –55°C to +125°C
Storage Temperature ..................................................... –55°C to +125°C
Junction Temperature ...................................................................... 150°C
Lead Temperature (soldering, 10s) ................................................. 300°C
This integrated circuit can be damaged by ESD. Burr-Brown
recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
NOTE: (1) Stresses above these rating may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability. (2) Short-circuit to ground, one amplifier per package.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits
may be more susceptible to damage because very small
parametric changes could cause the device not to meet its
published specifications.
PACKAGE/ORDERING INFORMATION
PRODUCT
OFFSET
VOLTAGE
max, µV
OFFSET
VOLTAGE DRIFT
max, µV/°C
PACKAGE
PACKAGE
DRAWING
NUMBER(1)
TEMPERATURE
RANGE
ORDERING
NUMBER(2)
TRANSPORT
MEDIA
Single
OPA277PA
OPA277P
OPA277UA
"
OPA277U
"
±50
±20
±50
"
±20
"
±1
±0.15
±1
"
±0.15
"
8-Pin DIP
8-Pin DIP
SO-8 Surface Mount
"
SO-8 Surface Mount
"
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
"
–40°C to +85°C
"
OPA277PA
OPA277P
OPA277UA
OPA277UA/2K5
OPA277U
OPA277U/2K5
Rails
Rails
Rails
Tape and Reel
Rails
Tape and Reel
Dual
OPA2277PA
OPA2277P
OPA2277UA
"
OPA2277U
"
±50
±25
±50
"
±25
"
±1
±0.25
±1
"
±0.25
"
8-Pin DIP
8-Pin DIP
SO-8 Surface Mount
"
SO-8 Surface Mount
"
006
006
182
"
182
"
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
"
–40°C to +85°C
"
OPA2277PA
OPA2277P
OPA2277UA
OPA2277UA/2K5
OPA2277U
OPA2277U/2K5
Rails
Rails
Rails
Tape and Reel
Rails
Tape and Reel
Quad
OPA4277PA
OPA4277UA
"
±50
±50
"
±1
±1
"
14-Pin DIP
SO-14 Surface Mount
"
010
235
"
–40°C to +85°C
–40°C to +85°C
"
OPA4277PA
OPA4277UA
OPA4277UA/2K5
Rails
Rails
Tape and Reel
NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Products followed by a slash
(/) are only available in Tape and Reel in the quantities indicated (e.g. /2K5 indicates 2500 devices per reel). Ordering 2500 pieces of “OPA277UA/2K5” will get
a single 2500 piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book.
®
3
OPA277, 2277, 4277
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted.
POWER SUPPLY AND COMMON-MODE
REJECTION vs FREQUENCY
OPEN-LOOP GAIN/PHASE
vs FREQUENCY
140
140
0
100
–30
80
–60
φ
60
–90
40
–120
20
–150
0
–180
120
+PSR
–PSR
PSR, CMR (dB)
AOL (dB)
120
CL = 0
CL = 1500pF
Phase (°)
G
100
80
CMR
60
40
20
0
–20
0.1
1
10
100
1k
10k
100k
1M
0.1
10M
1
10
100
1k
10k
100k
1M
Frequency (Hz)
Frequency (Hz)
INPUT NOISE AND CURRENT NOISE
SPECTRAL DENSITY vs FREQUENCY
INPUT NOISE VOLTAGE vs TIME
Noise signal is bandwidth limited to
lie between 0.1Hz and 10Hz.
Current Noise
100
50nV/div
Voltage Noise (nV/√Hz)
Current Noise (fA/√Hz)
1000
Voltage Noise
10
1
1
10
100
1k
10k
1sec/div
Frequency (Hz)
TOTAL HARMONIC DISTORTION + NOISE
vs FREQUENCY
CHANNEL SEPARATION vs FREQUENCY
1
140
120
THD+Noise (%)
Channel Separation (dB)
VOUT = 3.5Vrms
100
Dual and quad devices. G = 1,
all channels. Quad measured
channel A to D or B to C—other
combinations yield similar or
improved rejection.
80
60
0.1
G = 10, RL = 2kΩ, 10kΩ
0.01
G = 1, RL = 2kΩ, 10kΩ
0.001
40
10
100
1k
10k
100k
10
1M
Frequency (Hz)
1k
Frequency (Hz)
®
OPA277, 2277, 4277
100
4
10k
100k
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted.
OFFSET VOLTAGE DRIFT
PRODUCTION DISTRIBUTION
OFFSET VOLTAGE PRODUCTION DISTRIBUTION
16
12
Typical distribution
of packaged units.
Single, dual, and
quad included.
30
Percent of Amplifiers (%)
10
8
6
4
25
20
15
10
5
2
0
0
–50–45–40–35–30–25–20–15–10 –5 0 5 10 15 20 25 30 35 40 45 50
Offset Voltage (µV)
0
0.1
0.4
0.5
0.6
0.7
0.8
0.9
1.0
AOL, CMR, PSR vs TEMPERATURE
3
160
2
150
AOL, CMR, PSR (dB)
Offset Voltage Change (µV)
0.3
Offset Voltage (µV/°C)
WARM-UP OFFSET VOLTAGE DRIFT
1
0
–1
–2
CMR
140
AOL
130
PSR
120
110
–3
0
15
30
45
60
75
90
105
100
–75
120
–50
–25
0
25
50
75
100
Time from Power Supply Turn-On (s)
Temperature (°C)
INPUT BIAS CURRENT vs TEMPERATURE
QUIESCENT CURRENT AND
SHORT-CIRCUIT CURRENT vs TEMPERATURE
125
5
1000
100
4
950
90
3
900
80
Quiescent Current (µA)
Input Bias Current (nA)
0.2
2
1
0
–1
–2
Curves represent typical
production units.
70
850
±IQ
800
60
50
750
–ISC
700
40
+ISC
650
30
600
20
–4
550
10
–5
500
–75
–3
–75
–50
–25
0
25
50
75
100
125
Temperature (°C)
Short-Circuit Current (mA)
Percent of Amplifiers (%)
35
Typical distribution
of packaged units.
Single, dual, and
quad included.
14
0
–50
–25
0
25
50
75
100
125
Temperature (°C)
®
5
OPA277, 2277, 4277
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted.
CHANGE IN INPUT BIAS CURRENT
vs POWER SUPPLY VOLTAGE
CHANGE IN INPUT BIAS CURRENT
vs COMMON-MODE VOLTAGE
2.0
2.0
Curve shows normalized change in
bias current with respect to VS = ±10V
(+20V). Typical IB may range from
–0.5nA to +0.5nA at VS = ±10V.
1.5
1.0
VS = ±5V
0.5
0.0
∆IB (nA)
∆IB (nA)
1.0
Curve shows normalized change in bias current
with respect to VCM = 0V. Typical IB may range
from –05.nA to +0.5nA at VCM = 0V.
1.5
VCM = 0V
0.5
0.0
–0.5
–0.5
–1.0
–1.0
–1.5
–1.5
VS = ±15V
–2.0
–2.0
0
5
10
15
20
25
30
35
40
–15
–10
Supply Voltage (V)
QUIESCENT CURRENT vs SUPPLY VOLTAGE
5
10
15
100
10V step
CL = 1500pF
per amplifier
Settling Time (µs)
900
800
700
50
0.01%
0.1%
20
600
10
500
0
±5
±10
±15
±20
±1
±10
Supply Voltage (V)
±100
Gain (V/V)
MAXIMUM OUTPUT VOLTAGE
vs FREQUENCY
OUTPUT VOLTAGE SWING vs OUTPUT CURRENT
(V+)
30
(V+) – 1
Output Voltage Swing (V)
VS = ±15V
25
Output Voltage (Vp-p)
0
SETTLING TIME vs CLOSED-LOOP GAIN
1000
Quiescent Current (µA)
–5
Common-Mode Voltage (V)
20
15
10
VS = ±5V
5
–55°C
(V+) – 2
(V+) – 3
125°C
(V+) – 4
25°C
(V+) – 5
(V–) + 5
25°C
125°C
(V–) + 4
(V–) + 3
(V–) + 2
–55°C
(V–) + 1
(V–)
0
10k
1k
100k
1M
0
®
OPA277, 2277, 4277
±5
±10
±15
±20
Output Current (mA)
Frequency (Hz)
6
±25
±30
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, and RL = 2kΩ, unless otherwise noted.
LARGE-SIGNAL STEP RESPONSE
G = +1, CL = 1500pF, VS = ±15V
SMALL-SIGNAL OVERSHOOT
vs LOAD CAPACITANCE
60
Gain = –1
40
2V/div
Gain = +1
30
20
Gain = ±10
10
0
10
100
1k
10k
100k
10µs/div
Load Capacitance (pF)
SMALL-SIGNAL STEP RESPONSE
G = +1, CL = 1500pF, VS = ±15V
SMALL-SIGNAL STEP RESPONSE
G = +1, CL = 0, VS = ±15V
20mV/div
20mV/div
Overshoot (%)
50
1µs/div
1µs/div
®
7
OPA277, 2277, 4277
APPLICATIONS INFORMATION
connecting a potentiometer as shown in Figure 1. This
adjustment should be used only to null the offset of the op
amp. This adjustment should not be used to compensate for
offsets created elsewhere in a system since this can introduce additional temperature drift.
The OPA277 series is unity-gain stable and free from unexpected output phase reversal, making it easy to use in a wide
range of applications. Applications with noisy or high impedance power supplies may require decoupling capacitors
close to the device pins. In most cases 0.1µF capacitors are
adequate.
V+
Trim Range: Exceeds
Offset Voltage Specification
The OPA277 series has very low offset voltage and drift. To
achieve highest performance, circuit layout and mechanical
conditions should be optimized. Offset voltage and drift can
be degraded by small thermoelectric potentials at the op amp
inputs. Connections of dissimilar metals will generate thermal potential which can degrade the ultimate performance of
the OPA277 series. These thermal potentials can be made to
cancel by assuring that they are equal in both input terminals.
0.1µF
20kΩ
7
1
2
8
OPA277
3
0.1µF
4
6
OPA277 single op amp only.
Use offset adjust pins only to null
offset voltage of op amp—see text.
V–
• Keep thermal mass of the connections made to the two
input terminals similar.
• Locate heat sources as far as possible from the critical
input circuitry.
• Shield op amp and input circuitry from air currents such as
cooling fans.
FIGURE 1. OPA277 Offset Voltage Trim Circuit.
INPUT PROTECTION
The inputs of the OPA277 series are protected with 1kΩ
series input resistors and diode clamps. The inputs can
withstand ±30V differential inputs without damage. The
protection diodes will, of course, conduct current when the
inputs are over-driven. This may disturb the slewing behavior of unity-gain follower applications, but will not damage
the op amp.
OPERATING VOLTAGE
OPA277 series op amp operate from ±2V to ±18V supplies
with excellent performance. Unlike most op amps which are
specified at only one supply voltage, the OPA277 series is
specified for real-world applications; a single limit applies
over the ±5V to ±15V supply range. This allows a customer
operating at VS = ±10V to have the same assured performance as a customer using ±15V supplies. In addition, key
parameters are guaranteed over the specified temperature
range, –40°C to +85°C. Most behavior remains unchanged
through the full operating voltage range (±2V to ±18V).
Parameters which vary significantly with operating voltage
or temperature are shown in typical performance curves.
INPUT BIAS CURRENT CANCELLATION
The input stage base current of the OPA277 series is internally compensated with an equal and opposite cancellation
circuit. The resulting input bias current is the difference
between the input stage base current and the cancellation
current. This residual input bias current can be positive or
negative.
When the bias current is canceled in this manner, the input
bias current and input offset current are approximately the
same magnitude. As a result, it is not necessary to use a bias
current cancellation resistor as is often done with other op
amps (Figure 2). A resistor added to cancel input bias
current errors may actually increase offset voltage and noise.
OFFSET VOLTAGE ADJUSTMENT
The OPA277 series is laser-trimmed for very low offset
voltage and drift so most circuits will not require external
adjustment. However, offset voltage trim connections are
provided on pins 1 and 8. Offset voltage can be adjusted by
R2
R2
R1
R1
Op Amp
OPA277
RB = R2 || R1
No bias current
cancellation resistor
(see text)
(a)
(b)
Conventional op amp with external bias
current cancellation resistor.
OPA277 with no external bias current
cancellation resistor.
FIGURE 2. Input Bias Current Cancellation.
®
OPA277, 2277, 4277
8
V+
1/2
OPA2277
VOUT = (V1 – V2)(1 +
R2
R1
)
R2
V–
R–∆R
Load
Cell
V1
R+∆R
V+
R+∆R
V2
R1
1/2
OPA2277
R–∆R
V–
R2
R1
For integrated solution see: INA126, INA2126 (dual)
INA125 (on-board reference)
INA122 (single-supply)
FIGURE 3. Load Cell Amplifier.
IREG ∼ 1mA
5V
12
V+
Type J
VLIN
1/2
OPA2277
13
RF
10kΩ
4
R
412Ω
+
VIN
1
IR1
3
11
VREG
10
V+
RG
RG
1250Ω
RF
10kΩ
14
IR2
XTR105
B
E
RG
9
8
IO
1/2
OPA2277
1kΩ
2
25Ω
7
IRET
V–
50Ω
–
VIN
6
+
–
IO = 4mA + (VIN – VIN) 40
RG
RCM = 1250Ω
(G = 1 +
2RF
= 50)
R
0.01µF
FIGURE 4. Thermocouple Low Offset, Low Drift Loop Measurement with Diode Cold Junction Compensation.
®
9
OPA277, 2277, 4277
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