FEATURES
DLOW OFFSET VOLTAGE: 50µV max
DLOW DRIFT: 0.5µV/5C max
DLOW INPUT BIAS CURRENT: 5nA max
DHIGH CMR: 120dB min
DINPUTS PROTECTED TO +40V
DWIDE SUPPLY RANGE: +2.25V to +18V
DLOW QUIESCENT CURRENT: 700µA
D8-PIN PLASTIC DIP, SO-8
APPLICATIONS
DBRIDGE AMPLIFIER
DTHERMOCOUPLE AMPLIFIER
DRTD SENSOR AMPLIFIER
DMEDICAL INSTRUMENTATION
DDATA ACQUISITION
DESCRIPTION
The INA128 and INA129 are low power, general
purpose instrumentation amplifiers offering excellent
accuracy. The versatile 3-op amp design and small size
make them ideal for a wide range of applications.
Current-feedback input circuitry provides wide
bandwidth even at high gain (200kHz at G = 100).
A single external resistor sets any gain from 1 to 10,000.
The INA128 provides an industry-standard gain
equation; the INA129 gain equation is compatible with
the AD620.
The INA128/INA129 is laser trimmed for very low offset
voltage (50µV), drift (0.5µV/°C) and high
common-mode rejection (120dB at G ≥ 100). It
operates with power supplies as low as ±2.25V, and
quiescent current is only 700µA—ideal for battery-
operated systems. Internal input protection can
withstand up to ±40V without damage.
The INA128/INA129 is available in 8-pin plastic DIP and
SO-8 surface-mount packages, specified for the –40°C
to +85°C temperature range. The INA128 is also
available in a dual configuration, the INA2128.
A1
A2
A3
40kΩ
40kΩ
40kΩ
40kΩ
VIN
2
1
8
3
6
5
VIN
RG
V+
V
−
Ref
VO
G=1+49.4kΩ
RG
−
+
4
7
NOTE: (1) INA129: 24.7kΩ
G=1+ 50kΩ
RG
INA128, INA129
Over-Voltage
Protection
Over-Voltage
Protection
25kΩ(1)
25kΩ(1)
INA128:
INA129:
All trademarks are the property of their respective owners.
INA128
INA129
Precision, Low Power
INSTRUMENTATION AMPLIFIERS
SBOS051B − OCTOBER 1995 − REVISED FEBRUARY 2005
! !
www.ti.com
Copyright 1995−2005, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments
semiconductor products and disclaimers thereto appears at the end of this data sheet.
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SBOS051B − OCTOBER 1995 − REVISED FEBRUARY 2005
www.ti.com
2
ABSOLUTE MAXIMUM RATINGS(1)
Supply Voltage ±18V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Analog Input Voltage Range ±40V. . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Short-Circuit (to ground) Continuous. . . . . . . . . . . . . . . . . .
Operating Temperature −40°C to +125°C. . . . . . . . . . . . . . . . . . .
Storage Temperature Range −55°C to +125°C. . . . . . . . . . . . . . . . .
Junction Temperature +150°C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lead Temperature (soldering, 10s) +300°C. . . . . . . . . . . . . . . . . . . . .
(1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods
may degrade device reliability. These are stress ratings only, and
functional operation of the device at these or any other conditions
beyond those specified is not implied.
ELECTROSTATIC DISCHARGE SENSITIVITY
This integrated circuit can be damaged by
ESD. Texas Instruments recommends that all
integrated circuits be handled with appropriate
precautions. Failure to observe proper handling and
installation procedures can cause damage.
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.
ORDERING INFORMATION
For the most current package and ordering information, see the Package Option Addendum located at the end of this data
sheet.
PIN CONFIGURATION
RG
V−IN
V+IN
V−
RG
V+
VO
Ref
1
2
3
4
8
7
6
5
Top View
8-Pin DIP and SO-8
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SBOS051B − OCTOBER 1995 − REVISED FEBRUARY 2005
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3
ELECTRICAL CHARACTERISTICS
At TA = +25°C, VS = ±15V, RL = 10kΩ, unless otherwise noted.
INA128P, U
INA129P. U
INA128PA, UA
INA129PA, UA
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNIT
INPUT
Offset Voltage, RTI
Initial TA = +25°C±10±100/G ±50±500/G ±25±100/G ±125±1000/G µV
vs Temperature TA = TMIN to TMAX ±0.2±2/G ±0.5±20/G ±0.2±5/G ±1±20/G µV/°C
vs Power Supply VS = ±2.25V to ±18V ±0.2±20/G ±1±100/G ∗ ±2±200/G µV/V
Long-Term Stability ±0.1±3/G ∗ µV/mo
Impedance, Differential 1010 || 2 ∗ Ω || pF
Common-Mode 1011 || 9 ∗ Ω || pF
Common-Mode Voltage Range(1) VO = 0V (V+) − 2 (V+) − 1.4 ∗ ∗ V
(V−) + 2 (V−) + 1.7 ∗ ∗ V
Safe Input Voltage ±40 ∗V
Common-Mode Rejection VCM = ±13V, ∆RS = 1kΩ
G = 1 80 86 73 ∗dB
G = 10 100 106 93 ∗dB
G = 100 120 125 110 ∗dB
G = 1000 120 130 110 ∗dB
BIAS CURRENT ±2±5∗ ±10 nA
vs Temperature ±30 ∗pA/°C
Offset Current ±1±5∗ ±10 nA
vs Temperature ±30 ∗pA/°C
NOISE VOLTAGE, RTI G = 1000, RS = 0Ω
f = 10Hz 10 ∗nV/√Hz
f = 100Hz 8∗nV/√Hz
f = 1kHz 8∗nV/√Hz
fB = 0.1Hz to 10Hz 0.2 ∗ µVPP
Noise Current
f = 10Hz 0.9 ∗pA/√Hz
f = 1kHz 0.3 ∗pA/√Hz
fB = 0.1Hz to 10Hz 30 ∗pAPP
GAIN
Gain Equation, INA128 1 + (50kΩ/RG) ∗ V/V
Gain Equation, INA129 1 + (49.4kΩ/RG) ∗ V/V
Range of Gain 1 10000 ∗ ∗ V/V
Gain Error G = 1 ±0.01 ±0.024 ∗ ±0.1 %
G = 10 ±0.02 ±0.4 ∗ ±0.5 %
G = 100 ±0.05 ±0.5 ∗ ±0.7 %
G = 1000 ±0.5 ±1∗ ±2 %
Gain vs Temperature(2) G = 1 ±1±10 ∗ ∗ ppm/°C
50kΩ (or 49.4kΩ) Resistance(2)(3) ±25 ±100 ∗ ∗ ppm/°C
Nonlinearity VO = ±13.6V, G = 1 ±0.0001 ±0.001 ∗ ±0.002 % of FSR
G = 10 ±0.0003 ±0.002 ∗ ±0.004 % of FSR
G = 100 ±0.0005 ±0.002 ∗ ±0.004 % of FSR
G = 1000 ±0.001 (4) ∗ ∗ % of FSR
NOTE:∗ Specification is same as INA128P, U or INA129P, U.
(1) Input common-mode range varies with output voltage — see typical curves.
(2) Specified by wafer test.
(3) Temperature coefficient of the 50kΩ (or 49.4kΩ) term in the gain equation.
(4) Nonlinearity measurements in G = 1000 are dominated by noise. Typical nonlinearity is ±0.001%.
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SBOS051B − OCTOBER 1995 − REVISED FEBRUARY 2005
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4
ELECTRICAL CHARACTERISTICS (continued)
At TA = +25°C, VS = ±15V, RL = 10kΩ, unless otherwise noted.
INA128PA, UA
INA129PA, UA
INA128P, U
INA129P. U
PARAMETER UNITMAXTYPMINMAXTYPMINCONDITIONS
OUTPUT
Voltage: Positive RL = 10kΩ(V+) − 1.4 (V+) − 0.9 ∗ ∗ V
Voltage: Negative RL = 10kΩ(V−) + 1.4 (V−) + 0.8 ∗ ∗ V
Load Capacitance Stability 1000 ∗pF
Short-Circuit Current +6/−15 ∗mA
FREQUENCY RESPONSE
Bandwidth, −3dB G = 1 1.3 ∗MHz
G = 10 700 ∗kHz
G = 100 200 ∗kHz
G = 1000 20 ∗kHz
Slew Rate VO = ±10V, G = 10 4∗V/µs
Settling Time, 0.01% G = 1 7∗ µs
G = 10 7∗ µs
G = 100 9∗ µs
G = 1000 80 ∗ µs
Overload Recovery 50% Overdrive 4∗ µs
POWER SUPPLY
Voltage Range ±2.25 ±15 ±18 ∗ ∗ ∗ V
Current, Total VIN = 0V ±700 ±750 ∗ ∗ µA
TEMPERATURE RANGE
Specification −40 +85 ∗ ∗ °C
Operating −40 +125 ∗ ∗ °C
qJA 8-Pin DIP 80 ∗ °C/W
SO-8 SOIC 150 ∗ °C/W
NOTE:∗ Specification is same as INA128P, U or INA129P, U.
(1) Input common-mode range varies with output voltage — see typical curves.
(2) Specified by wafer test.
(3) Temperature coefficient of the 50kΩ (or 49.4kΩ) term in the gain equation.
(4) Nonlinearity measurements in G = 1000 are dominated by noise. Typical nonlinearity is ±0.001%.
