LT1990 Datasheet

• Pin Selectable Gain of 1 or 10
• High Common Mode Voltage Range:
  • 85V Window (V_S = 5V, 0V)
  • ±250V (V_S = ±15V)
• Common Mode Rejection Ratio: 70dB Min
• Input Protection to ±350V
• Gain Error: 0.28% Max
• PSRR: 82dB Min
• High Input Impedance: 2MΩ Differential, 500kΩ Common Mode
• Micropower: 120µA Max Supply Current
• Wide Supply Range: 2.7V to 36V
• –3dB Bandwidth: 100kHz
• Rail-to-Rail Output
• 8-Pin SO Package

• Battery Cell Voltage Monitoring
• High Voltage Current Sensing
• Signal Acquisition in Noisy Environments
• Input Protection
• Fault Protected Front Ends
• Level Sensing
• Isolation

The LT1990 is a micropower precision difference amplifier with a very high common mode input voltage range. It has pin selectable gains of 1 or 10. The LT1990 operates over a ±250V common mode voltage range on a ±15V supply. The inputs are fault protected from common mode voltage transients up to ±350V and differential voltages up to ±500V. The LT1990 is ideally suited for both high side and low side current or voltage monitoring.

On a single 5V supply, the LT1990 has an adjustable 85V input range, 70dB min CMRR and draws less than 120µA supply current. The rail-to-rail output maximizes the dynamic range, especially important for single supplies as low as 2.7V.

The LT1990 is specified for single 3V, 5V and ±15V supplies over both commercial and industrial temperature ranges. The LT1990 is available in the 8-pin SO package.