Power by Linear™ / Analog Devices’ LT1997-2 is an attenuating (funnel) difference amplifier that can be used to translate large differential signals to the low voltage range compatible with ADCs. The LT1997IDF-3#PBF combines a precision operational amplifier with highly-matched resistors to form a one-chip solution for accurately amplifying voltages.The LT1997-2 combines a precision operational amplifier with highly-matched resistors to form a one-chip solution to attenuate and level shift voltages accurately using no external components. It comes with three standard pin-selectable gain options (0.1, 0.2, and 0.25), which can be further combined to form gains from 0.0455 to 0.55 (attenuations of 1.82 to 22) with accuracy of 0.006% (60 ppm). The LT1997-2 also works across a very wide input common-mode voltage range (±255 V), enabling robust operation in demanding industrial environments. Its excellent resistor matching results in a common mode rejection ratio of greater than 105 dB.The LT1997IDF-3#PBF is particularly well suited for use as a difference amplifier, where the excellent resistor matching results in a common mode rejection ratio of greater than 91dB. The amplifier features a 60 μV maximum input offset voltage and a -3 dB bandwidth of 1.1 MHz (gain = 1). The LT1997IDF-3#PBF operates from any supply voltage from 3.3 V to 50 V and draws only 350 μA supply current. The output typically swings to within 100 mV of either supply rail.The LT1997 is fully specified at 5 V and ±15 V supplies and from -40°C to +125°C. These devices are available in 16-lead MSOP and 4 mm × 4 mm DFN14 packages. The LT1997 is ideal for high side low sensing, ADC drivers, and industrial data-acquisition front-ends.
Feature
- Pin Configurable as a Difference Amplifier, Inverting Amplifier or Noninverting Amplifier
- 91dB Minimum DC CMRR (Gain = 1)
- 65dB AC CMRR (at 100kHz, Gain = 1)
- 0.006% (60ppm) Maximum Gain Error (Gain = 1)
- 1ppm/°C Maximum Gain Error Drift
- 2ppm Maximum Gain Nonlinearity
- ±160V Common Mode Voltage Range
- Wide Supply Voltage Range: 3.3V to 50V
- Rail-to-Rail Output
- 350μA Supply Current
- 60μV Maximum Op Amp Offset Voltage
- 1.1MHz –3dB Bandwidth (Gain = 1)
- Low-Power Shutdown: 20μA
- Space-Saving MSOP and DFN Packages
Applications
- High Side or Low Side Current Sensing
- Bidirectional Wide Common Mode Range Current Sensing
- High Voltage to Low Voltage Level Translation
- Industrial Data-Acquisition Front-Ends
- Replacement for Isolation Circuits
- Differential to Single-Ended Conversion