參數(shù)資料
型號: ISO165
元件分類: 測量放大器
英文描述: Precision Instrumentation Amplifier
中文描述: 精密儀表放大器
文件頁數(shù): 8/8頁
文件大?。?/td> 164K
代理商: ISO165
8
ISO165/ISO175
“Signal Response vs Carrier Frequency” performance curve.
This occurs because IMV-induced errors behave like input-
referred error signals. To predict the total IMR, divide the
isolation voltage by the IMR shown in “IMR vs Frequency”
performance curve and compute the amplifier response to
this input-referred error signal from the data given in the
“Signal Response vs Carrier Frequency” performance curve.
Due to effects of very high-frequency signals, typical IMV
performance can be achieved only when dV/dT of the
isolation mode voltage falls below 1000V/
μ
s. For conve-
nience, this is plotted in the typical performance curves
for the ISO165 and ISO175 as a function of voltage and
frequency for sinusoidal voltages. When dV/dT exceeds
1000V/
μ
s but falls below 20kV/
μ
s, performance may be
degraded. At rates of change above 20kV/
μ
s, the amplifier
may be damaged, but the barrier retains its full integrity.
Lowering the power supply voltages below
±
15V may
decrease the dV/dT to 500V/
μ
s for typical performance, but
the maximum dV/dT of 20kV/
μ
s remains unchanged.
Leakage current is determined solely by the impedance of
the barrier capacitance and is plotted in the “Isolation Leak-
age Current vs Frequency” curve.
ISOLATION VOLTAGE RATINGS
Because a long-term test is impractical in a manufacturing
situation, the generally accepted practice is to perform a
production test at a higher voltage for some shorter time.
The relationship between actual test voltage and the continu-
ous derated maximum specification is an important one.
Historically, Burr-Brown has chosen a deliberately conser-
vative one: VTEST = (2 x ACrms continuous rating) +
1000V for 10 seconds, followed by a test at rated ACrms
voltage for one minute. This choice was appropriate for
conditions where system transients are not well defined.
Recent improvements in high-voltage stress testing have
produced a more meaningful test for determining maximum
permissible voltage ratings, and Burr-Brown has chosen to
apply this new technology in the manufacture and testing of
the ISO165 and ISO175.
PARTIAL DISCHARGE
When an insulation defect such as a void occurs within an
insulation system, the defect will display localized corona or
ionization during exposure to high-voltage stress. This ion-
ization requires a higher applied voltage to start the
discharge and lower voltage to maintain it or extinguish it
once started. The higher start voltage is known as the
inception voltage, while the extinction voltage is that level
of voltage stress at which the discharge ceases. Just as the
total insulation system has an inception voltage, so do the
individual voids. A voltage will build up across a void until
its inception voltage is reached, at which point the void will
ionize, effectively shorting itself out. This action redistrib-
utes electrical charge within the dielectric and is known as
partial discharge. If, as is the case with AC, the applied
voltage gradient across the device continues to rise, another
partial discharge cycle begins. The importance of this
phenomenon is that, if the discharge does not occur, the
insulation system retains its integrity. If the discharge be-
gins, and is allowed to continue, the action of the ions and
electrons within the defect will eventually degrade any
organic insulation system in which they occur. The measure-
ment of partial discharge is still useful in rating the devices
and providing quality control of the manufacturing process.
The inception voltage for these voids tends to be constant, so
that the measurement of total charge being redistributed
within the dielectric is a very good indicator of the size of the
voids and their likelihood of becoming an incipient failure.
The bulk inception voltage, on the other hand, varies with
the insulation system, and the number of ionization defects
and directly establishes the absolute maximum voltage (tran-
sient) that can be applied across the test device before
destructive partial discharge can begin. Measuring the bulk
extinction voltage provides a lower, more conservative volt-
age from which to derive a safe continuous rating. In
production, measuring at a level somewhat below the ex-
pected inception voltage and then derating by a factor
related to expectations about system transients is an ac-
cepted practice.
PARTIAL DISCHARGE TESTING
Not only does this test method provide far more qualitative
information about stress-withstand levels than did previous
stress tests, but it provides quantitative measurements from
which quality assurance and control measures can be based.
Tests similar to this test have been used by some manufac-
turers, such as those of high-voltage power distribution
equipment, for some time, but they employed a simple
measurement of RF noise to detect ionization. This method
was not quantitative with regard to energy of the discharge,
and was not sensitive enough for small components such as
isolation amplifiers. Now, however, manufacturers of HV
test equipment have developed means to quantify partial
discharge. VDE in Germany, an acknowledged leader in
high-voltage test standards, has developed a standard test
method to apply this powerful technique. Use of partial
discharge testing is an improved method for measuring the
integrity of an isolation barrier.
To accommodate poorly-defined transients, the part under
test is exposed to voltage that is 1.6 times the continuous-
rated voltage and must display less than or equal to 5pC
partial discharge level in a 100% production test.
APPLICATIONS
The ISO165 and ISO175 isolation amplifiers are used in
three categories of applications:
Accurate isolation of signals from high voltage ground
potentials,
Accurate isolation of signals from severe ground noise and,
Fault protection from high voltages in analog measure-
ments.
相關(guān)PDF資料
PDF描述
ISO166P Precision, Isolated OPERATIONAL AMPLIFIER
ISO166
ISO175P Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier
ISO175 Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier
ISO176P Precision, Isolated OPERATIONAL AMPLIFIER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ISO165/ISO175 制造商:未知廠家 制造商全稱:未知廠家 功能描述:ISO165. ISO175 - DISCONTINUED PRODUCT. No longer recommended for new design.
ISO166 制造商:未知廠家 制造商全稱:未知廠家 功能描述:
ISO166/ISO176 制造商:未知廠家 制造商全稱:未知廠家 功能描述:ISO166. ISO176 - DISCONTINUED PRODUCT. No longer recommended for new design.
ISO166P 制造商:BB 制造商全稱:BB 功能描述:Precision, Isolated OPERATIONAL AMPLIFIER
ISO16-GM-391 功能描述:繼電器插座與硬件 RELAY ISO x16 GADGETEER MODULE RoHS:否 制造商:TE Connectivity / Schrack 附件類型:Socket 相關(guān)繼電器系列:RP, RT, RY 端接類型:PCB 極數(shù):1