1 Features
• Ultra-low 0.95 nV/√ Hz voltage noise
• High Speed:
– 180-MHz unity gain bandwidth
– 140-MHz bandwidth [G = 2 (–1), –3 dB]
– 105-V/μs slew rate
• Very low distortion
– THD = –91 dBc (f = 1 MHz, RL = 150 Ω)
– THD = –100 dBc (f = 1 MHz, RL = 1 kΩ)
– THD+N = =137 dBc (f = 1 kHz, BW = 80 kHz)
• Low 0.2-mV (typical) and 1-mV (max) input offset
voltage at 25°C
• 200-mA output current drive (typical)
• Typical operation from ±4.5 V to ±18 V
• 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 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 dualamplifier
OPA2891 offer very good ac performance
with 140-MHz bandwidth (G = 2), 105-V/μs slew
rate, and 70-ns settling time (0.1%). The OPAx891
are unity-gain stable with 180-MHz bandwidth. These
amplifiers have a high drive capability of 200 mA and
draw only 7.5-mA supply current per channel. With
–100 dBc of total harmonic distortion (THD) at f =
1 MHz and a very low noise of 0.95 nV/√ Hz, the
OPAx891 are designed for applications requiring low
distortion and low noise such as buffering analog-todigital
converters.