1FEATURES
• Wide Bandwidth (80MHz, Open-Loop, G = +5)
• High Slew Rate (900V/μs)
• High Transconductance (95mA/V) self•
External I Q-Control
• Low Quiescent Current (5.4mA)

APPLICATIONS
• Video/Broadcast Equipment
• Communications Equipment
• High-Speed Data Acquisition
• Wideband LED Drivers
• Control Loop Amplifiers
• Wideband Active Filters
• Line Drivers

DESCRIPTION
The OPA861 is a versatile monolithic component
designed for wide-bandwidth systems, including high
performance video, RF and IF circuitry. The OPA861
is a wideband, bipolar operational transconductance
amplifier (OTA).
The OTA or voltage-controlled current source can be
viewed as an ideal transistor. Like a transistor, it has
three terminals—a high impedance input (base), a
low-impedance input/output (emitter), and the current
output (collector). The OPA861, however, is self•
biased and bipolar. The output collector current is
zero for a zero base-emitter voltage. AC inputs
centered about zero produce an output current, which
is bipolar and centered about zero. The
transconductance of the OPA861 can be adjusted
with an external resistor, allowing bandwidth,
quiescent current, and gain trade-offs to be
optimized.
Used as a basic building block, the OPA861
simplifies the design of AGC amplifiers, LED driver
circuits for fiber optic transmission, integrators for fast
pulses, fast control loop amplifiers and control
amplifiers for capacitive sensors, and active filters.
The OPA861 is available in SO-8 and SOT23-6
surface-mount packages.