1 Features
• High speed:
– Gain-bandwidth product (GBWP): 2.7GHz
– Bandwidth (G = 7V/V): 765MHz
– Large-signal bandwidth (2VPP): 400MHz
– Slew rate: 1400V/μs
• Decompensated gain: 7V/V stable
• Low noise:
– Input voltage noise: 2.2nV/√Hz
– Input current noise: 3fA/√Hz (f = 10kHz)
• Input bias current: 4pA (typical)
• Low input capacitance:
– Common-mode: 1.9pF
– Differential mode: 0.5pF
• Low distortion (G = 7V/V, RL = 1kΩ, VO = 2VPP):
– HD2, HD3 at 1MHz: –104dBc, –108dBc
– HD2, HD3 at 50MHz: –57dBc, –72dBc
• Wide supply range: 6V to 13V
• Output swing: 8VPP (VS = 10V)
• Supply current: 27.7mA
• Shutdown supply current: 27μA
• Performance upgrade to OPA657

2 Applications
• Wideband transimpedance amplifier (TIA)
• Wafer scanning equipment
• Optical communication module
• High-speed data acquisition (DAQ)
• Active probe
• Optical time-domain reflectometry (OTDR)
• Test and measurement front-end
• Medical and chemical analyzer

3 Description
The OPA818 is a decompensated, voltage-feedback
operational amplifier for high-speed and widedynamic-
range applications. The OPA818 has a
low-noise JFET input stage that combines high
gain-bandwidth with a wide supply range from 6V
to 13V. The fast slew rate (1400V/μs) provides
high, large-signal bandwidth and low distortion. This
amplifier is manufactured using TI's proprietary, highspeed,
silicon-germanium (SiGe) process to achieve
significant performance improvements over other
high-speed, FET-input amplifiers.
The OPA818 is an extremely versatile, wideband
TIA photodiode amp for use in optical test and
communication equipment, and many medical,
scientific, and industrial instruments. The OPA818
showcases a 2.7GHz GBWP, low 2.4pF total input
capacitance, and 2.2nV/√Hz input noise. The OPA818
achieves over 85MHz signal bandwidth in a TIA
configuration with 20kΩ TIA gain (RF) and 0.5pF
photodiode capacitance (CD) with wide output swings.
The low-noise architecture with picoampere of input
bias current is also an excellent choice for test and
measurement applications. Though typically stable in
gains ≥ 7V/V, the OPA818 is designed for use in
applications with lower gains by applying noise-gain
shaping techniques.
The OPA818 is available in an 5-pin SOT-23 package
and an 8-lead WSON package with an exposed
thermal pad for heat dissipation. This device is
specified for operation over the industrial temperature
range of –40°C to +85°C.