277_15 Datasheet, PDF (1/4 Pages) Analog Devices – Precision Isolation Amplifier

--. ANALOG
PrecisionIsolationAmplifier
W DEVICES _{HighCMVjCMR,+15VFloatingPower}
MODEL2;77
FEATURES
Versatile Op Amp Front End: Inverting, Non-Inverting,
Differential Applicatrons
low Nonlinearity: 0.025% max, Model 277K
low Input Offset Voltage Drift: 1p.VtC max, Model 217K
Floating Power Output: :!:15V @ :!:15mA
High CMR: 160dB min @dc
High CMV: 3500Vrms
OBSOLETE APPLICATIONS
Programmable Gain Isolated Amplifier
Isolated Power Source and Amplifier for Bridge Measurements
Instrumentation Amplifier
Instrumentation Grade Process Signal Isolator
Current Shunt Measurements
GENERAL DESCRIPTION
Model 277 is a versatile isolation amplifier which combines a
high-performance, uncommitted operational amplifier front
end with a precision, isolated output stage and a floating power
supply section. This configuration, shown in Figure 1, makes
the 277 ideally suited to instrumentation applications where
the need for various forms of signal conditioning, high CMV
protection and isolated transducer power requirements are
encountered.
combined with the output stage's low nonlinearity (0.05%,
models 277]/A and 0.025% model 277K), these high CMR and
CMV ratings facilitate accurate measurem<:nts in the presence
of noisy electrical equipment such as motors and relays. In
addition, model 277A offers a -25°C to +85°C rated operating
temperature range. All versions of model 277 have a :!:10 volt
output range.
The floating power supply section provides isolated :!:15volt
outputs capable of delivering currents up to :!:15mA. This
The input stage is a low drift (:!:Ip.V/C max, model 277K)
feature permits model 277 to power transcucers and auxilliary
differential op amp that may be connected for use in inverting, _{isolated circuitry, thereby eliminating the need for a separate}
non-inverting and differential configurations. The circuitry
isolated DC/DC converter.
employed around the operational amplifier input stage can be
designed by the user to suit each application's particular signal
processing needs. A full :!:10V signal range is available at the
output of the front end amplifier.
All of the features of the model 277 isolation amplifier are
packaged in a compact (3" x 2.2" x 0.59") module. As an
assurance of high performance reliability, every model 277 is
factory tested for CMV rating by application of 35OOVDDS
OUT
OFFSErTRIM
OUT
GAIN TRIM
(:!:4900V peak) between input and output common terminals
for one minute (meets NEMA and CSA requirements for
660V ans service.) In addition, the 277 has a calculated MTBF
of 133,000 hours.
PWR COM
Figure 1. Model 277 Functional Block Diagram
The isolated output stage includes a special modulator/demodu-
lator technique which provides the 277 with 160dB minimum
DC common mode rejection between input and output com-
mon and an input-to-output CMV rating of 3500V ans. When
Information furnished by Analog Devices is believed to be accurate
and reliable. Hovvever, no responsibility is assumed by Analog Devices
for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implica'
tion or otherwise under any patent or patent rights of Analog Devices.
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