Analog Devices, Inc.

LT1997 Gain Selectable Funnel Amplifiers

Analog Devices’ amplifiers for high side low sensing, ADC drivers, and industrial data-acquisition front-ends

Image of Analog Devices LT1997 Gain Selectable Funnel AmplifiersAnalog 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 LT1997-3 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 LT1997-3 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 LT1997-3 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.

Image of Analog Devices LT1997 Gain Selectable Funnel Amplifiers Diagram (click to enlarge) Image of Analog Devices LT1997 Gain Selectable Funnel Amplifiers Graph
Features Applications
  • •Precision attenuation: gain = 0.1, 0.2, 0.25
  • •±255 V common mode voltage range
  • •91 dB/105 dB minimum CMRR (gain = 0.1)
  • •0.006% (60 ppm) maximum gain error
  • •1 ppm/°C maximum gain error drift
  • •2 ppm maximum gain nonlinearity
  • •Voltage supply range: 3.3 V to 50 V
  • •Rail-to-rail output
  • •350 μA supply current
  • •60 μ/80 μV maximum op amp offset voltage
  • •1 MHz -3 dB bandwidth (gain = 0.1)
  • •Low power shutdown: 20 μA
  • •MSOP and DFN packages
  • ADC driver
  • High voltage to low voltage level translation
  • Bidirectional wide common mode range voltage and current sensing
  • Industrial data-acquisition front-ends
  • Replacement for isolation circuits
  • Differential to single-ended conversion
  • High side or low side current sensing

LT1997 Gain Selectable Funnel Amplifiers

ImageManufacturer Part NumberDescriptionAvailable QuantityPriceView Details
IC OPAMP GP 1 CIRCUIT 14DFNLT1997HDF-2#PBFIC OPAMP GP 1 CIRCUIT 14DFN77 - Immediate$10.32View Details
IC OPAMP GP 1 CIRCUIT 14DFNLT1997IDF-2#PBFIC OPAMP GP 1 CIRCUIT 14DFN202 - Immediate$9.03View Details

Evaluation Board

ImageManufacturer Part NumberDescriptionAmplifier TypeOutput TypeSlew RateAvailable QuantityPriceView Details
DEMO BOARD FOR LT1997DC2551A-ADEMO BOARD FOR LT1997General PurposeSingle-Ended, Rail-to-Rail0.75V/µs1 - Immediate$54.34View Details
Published: 2018-08-14

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