Precision, Wide Voltage Range Gain Selectable Amplifier

The LT1997-3 combines a precision operational amplifier 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 no external components. 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 60μV maximum input offset voltage and a -3dB bandwidth of 1.1MHz (Gain = 1). The LT1997-3 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.

The resistors maintain their excellent matching over temperature; the matching temperature coefficient is guaranteed less than 1ppm/°C. The resistors are extremely linear with voltage, resulting in a gain nonlinearity of less than 2ppm.

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.

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

* 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