±270V Common Mode Difference Amplifier Features 97dB Min CMRR, ±35ppm Max Gain Error

Linear Technology LT6375

Linear Technology introduces the LT6375, a unity-gain difference amplifier with integrated precision matched resistors, which precisely level shifts and buffers small difference signals while rejecting up to ±270 V common mode. The A-grade version achieves unprecedented performance: CMRR is 97 dB (min), initial gain error is 35 ppm (max), gain drift is 1 ppm/°C (max) and gain nonlinearity is 2 ppm (max) with a common mode divide ratio of 25:1. The common mode divide ratio is selectable from 7:1 to 25:1, enabling the designer to select the ratio with the best performance for a given common mode input range.

Linear Technology - LT6375

At the heart of the LT6375 is a high precision Over-The-Top amplifier which operates with inputs both within and above the 3.3 V to 50 V supply voltage. This permits the combination of a wide input range and low voltage supply. Use of a low voltage supply limits power consumption and protects downstream circuitry from high voltage.

“The LT6375 combines a high precision, wide voltage range Over-The-Top amplifier with configurable precision matched resistors,” says Maziar Tavakoli, Design Manager, Signal Conditioning Products. “With seven different divider ratios to choose from, precision, noise and speed can be optimized for specific input range requirements. For example, if the input common mode range is ±80 V, a resistor divider ratio of seven may be selected to achieve lower noise, lower offset, and wider bandwidth than is achievable with a ratio of 20.”

Precision Wide Voltage Range, Bidirectional Current Monitor 
Precision Wide Voltage Range, Bidirectional Current Monitor.

The LT6375 includes many other useful features, including rail-to-rail outputs, low supply current and a shutdown mode. It is available in a 4 mm × 4 mm 12-lead DFN and a 4 mm long MSOP package with 12 leads. Both packages include skipped leads for extra spacing of high voltage input signals.

The LT6375 is fully specified over the –40 °C to 85 °C (I-grade) and –40 °C to 125 °C (H-grade) temperature ranges, priced starting at $2.95 each in 1,000 piece quantities.

Summary of Features: LT6375

  • ±270 V Common Mode Voltage Range
    • Outstanding Precision:
    • CMRR
      • 97 dB Minimum (A-Grade)
      • 90 dB Minimum (B-Grade)
    • Gain Error
      • 0.0035% Maximum (35 ppm) (A-Grade)
      • 0.006% Maximum (60 ppm) (B-Grade)
    • Gain Error Drift: 1 ppm/°C Maximum
    • Gain Nonlinearity: 2 ppm Maximum
    • Offset Voltage
      • 300 μV Maximum (A-Grade, Resistor Divide Ratio = 7)
      • 450 μV Maximum (B-Grade, Resistor Divide Ratio = 7)
  • Wide Supply Voltage Range: 3.3 V to 50 V
  • Rail-to-Rail Output
  • 350 μA Supply Current
  • Selectable Internal Resistor Divider Ratio
  • 575 kHz –3 dB Bandwidth (Resistor Divider = 7)
  • 375 kHz –3 dB Bandwidth (Resistor Divider = 20)
  • –40 °C to 125 °C Specified Temperature Range
  • Low Power Shutdown: 20 μA (DFN Package)
  • Space-Saving MSOP and DFN Packages

1-4 Layer PCBs $2

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