• Ultra-low 0.95nV/√Hz voltage noise
• High speed:
  • 180MHz unity gain bandwidth
  • 140MHz bandwidth at a gain of 2V/V (–1V/V)
  • 105V/μs slew rate
• Very low distortion
  • THD = –91dBc (f = 1MHz, R_L = 150Ω)
  • THD = –100dBc (f = 1MHz, R_L = 1kΩ)
  • THD+N = –137dBc (f = 1kHz, BW = 80kHz)
• Low 0.2mV (typical) and 1mV (maximum) input offset voltage at 25°C
• 200mA output current drive (typical)
• Typical operation from ±4.5V to ±18V
• Offset nulling pins on the OPA891

• Low-noise, wide-band amplifier for industrial applications
• Voltage-controlled oscillators
• Active filters
• Video amplifiers
• Cable drivers
• Ultrasound scanners
• Vector signal transceiver (VST)
• Professional audio mixer or control surface
• Professional microphones and wireless systems
• Professional speaker systems
• Professional audio amplifier
• Soundbar
• Turntable
• Professional video camera
• Guitar and other instrument amplifier
• Data acquisition (DAQ)

The OPA891 and OPA2891 (OPAx891) are ultra-low voltage noise, high-speed voltage feedback amplifiers that are an excellent choice for applications requiring low voltage noise, including communications and imaging. The single-amplifier OPA891 and the dual-amplifier OPA2891 offer very good ac performance with 140MHz bandwidth, gain (G) = 2V/V, 105V/μs slew rate, and 70ns settling time (0.1%). The OPAx891 are unity-gain stable with 180MHz bandwidth. These amplifiers have a high drive capability of 200mA and draw only 7.5mA supply current per channel. With –100dBc of total harmonic distortion (THD) at f = 1MHz and a very low noise of 0.95nV/√Hz, the OPAx891 are designed for applications requiring low distortion and low noise such as buffering analog-to-digital converters.

Ultrasound Time-Gain-Control Circuit

Voltage and Current Noise vs Frequency