LT1997-3
Precision, Wide Voltage
Range Gain Selectable
Amplifier
FeaTures
DescripTion
TheLT®1997-3combinesaprecisionoperationalamplifier
with highly-matched resistors to form a one-chip solution
for accurately amplifying voltages. Gains from –13 to +14
with accuracy of 0.006% (60ppm) can be achieved using
noexternalcomponents. TheLT1997-3isparticularlywell
suited for use as a difference amplifier, where the excellent
resistor matching results in a common mode rejection
ratio of greater than 91dB.
n
Pin Configurable as a Difference Amplifier, Inverting
Amplifier or Noninverting Amplifier
n
91dB Minimum DC CMRR (Gain = 1)
n
65dB AC CMRR (at 100kHz, Gain = 1)
n
0.006% (60ppm) Maximum Gain Error (Gain = 1)
n
1ppm/°C Maximum Gain Error Drift
n
2ppm Maximum Gain Nonlinearity
n
160V Common Mode Voltage Range
n
Wide Supply Voltage Range: 3.3V to 50V
Theamplifierfeaturesa60μVmaximuminputoffsetvoltage
anda–3dBbandwidthof1.1MHz(Gain=1).TheLT1997-3
operates from any supply voltage from 3.3V to 50V and
draws only 350μA supply current. The output typically
swings to within 100mV of either supply rail.
n
Rail-to-Rail Output
350µA Supply Current
n
n
60µV Maximum Op Amp Offset Voltage
n
1.1MHz –3dB Bandwidth (Gain = 1)
n
Low-Power Shutdown: 20µA
n
The resistors maintain their excellent matching over
temperature; the matching temperature coefficient is
guaranteedlessthan1ppm/°C.Theresistorsareextremely
linear with voltage, resulting in a gain nonlinearity of less
than 2ppm.
Space-Saving MSOP and DFN Packages
applicaTions
n
High Side or Low Side Current Sensing
n
Bidirectional Wide Common Mode Range Current
The LT1997-3 is fully specified at 5V and 15V supplies
and from –40°C to 125°C. The device is available in space
saving 16-lead MSOP and 4mm × 4mm DFN14 packages.
L, LT, LTC, LTM, Linear Technology, Over-The-Top and the Linear logo are registered
trademarks of Analog Devices, Inc. All other trademarks are the property of their respective
owners.
Sensing
n
n
n
n
High Voltage to Low Voltage Level Translation
Industrial Data-Acquisition Front-Ends
Replacement for Isolation Circuits
Differential to Single-Ended Conversion
Typical applicaTion
Typical Distribution of CMRR (G = 1)
Gain = 1 Difference Amplifier
1200
V
= –28V TO 26.5V
15V
SOURCE
V
= ±±1V
S
V
CM
= –28V TO +26.1V
+
–INA –INB –INC
V
LT1997-3
1000
800
600
400
200
0
4621 UNITS
2.5k
7.5k
FROM 3 RUNS
22.5k
22.5k
22.5k
–
+
OUT
R
R
C
SENSE
V
OUT
= 1ꢀV/ꢀA
1Ω
1Ω
7.5k
2.5k
45k
45k
REF2
REF1
LOAD
–30
–20
–10
0
10
20
30
–
V
CMRR (µV/V = ppm)
+INA +INB +INC
SHDN
19973 TA01b
19973 TA01a
–15V
19973f
1
For more information www.linear.com/LT1997-3