1 Features
• 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, RL = 150Ω)
– THD = –100dBc (f = 1MHz, RL = 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

2 Applications
• 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)

3 Description
The OPA891 and OPA2891 (OPAx891) are ultralow
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.