1FEATURES
2• Common-Mode Voltage Range: ±275 V
• Minimum CMRR: 90 dB from –40°C to +125°C
• DC Specifications:
– Maximum Offset Voltage: 1100 μV
– Maximum Offset Voltage Drift: 15 μV/°C
– Maximum Gain Error: 0.02%
– Maximum Gain Error Drift: 10 ppm/°C
– Maximum Gain Nonlinearity: 0.001% FSR
• AC Performance:
– Bandwidth: 500 kHz
– Typical Slew Rate: 5 V/μs
• Wide Supply Range: ±2.0 V to ±18 V
– Maximum Quiescent Current: 900 μA
– Output Swing on ±15-V Supplies: ±13.5 V
• Input Protection:
– Common-Mode: ±500 V
– Differential: ±500 V

APPLICATIONS
• High-Voltage Current Sensing
• Battery Cell Voltage Monitoring
• Power-Supply Current Monitoring
• Motor Controls
• Replacement for Isolation Circuits

DESCRIPTION
The INA149 is a precision unity-gain difference
amplifier with a very high input common-mode
voltage range. It is a single, monolithic device that
consists of a precision op amp and an integrated thin-
film resistor network. The INA149 can accurately
measure small differential voltages in the presence of common-mode signals up to ±275 V. The INA149
inputs are protected from momentary common-mode
or differential overloads of up to 500 V.
In many applications, where galvanic isolation in not
required, the INA149 can replace isolation amplifiers.
This ability can eliminate costly isolated input side power supplies and the associated ripple, noise, and
quiescent current. The excellent 0.0005% nonlinearity
and 500-kHz bandwidth of the INA149 are superior to
those of conventional isolation amplifiers.
The INA149 is pin-compatible with the INA117 and
INA148 type high common-mode voltage amplifiers and offers improved performance over both devices.
The INA149 is available in the SOIC-8 package with
operation specified over the extended industrial
temperature range of –40°C to +125°C.