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參數資料
| 型號： | ISO175 |
| 元件分類： | 測量放大器 |
| 英文描述： | Single Supply, Rail-to-Rail, Low Cost Instrumentation Amplifier |
| 中文描述： | 單電源，軌至軌，低成本儀表放大器 |
| 文件頁數： | 8/8頁 |
| 文件大小： | 160K |
| 代理商： | ISO175 |
8
ISO175
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 curve
for the 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 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
begins, 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 ISO175 isolation amplifier is 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PDF資料 |
PDF描述 |
|---|---|
| ISO176P | Precision, Isolated OPERATIONAL AMPLIFIER |
| ISO176 | |
| ISO212JP-15 | 30/PG/CL/BECU/LL/FLNG/THD INSERT/30AVG |
| ISO212KP | Low Cost, Two-Port Isolated, 1500Vrms ISOLATION AMPLIFIER |
| ISO212 | |
相關代理商/技術參數 |
參數描述 |
|---|---|
| ISO175P | 制造商:BB 制造商全稱:BB 功能描述:Precision, Isolated INSTRUMENTATION AMPLIFIER |
| ISO176 | 制造商:BB 制造商全稱:BB 功能描述:Precision, Isolated OPERATIONAL AMPLIFIER |
| ISO176P | 制造商:Texas Instruments 功能描述:ISOLATION AMPLIFIER, 16 Pin, Plastic, DIP |
| ISO1H801G | 功能描述:電源開關 IC - 配電 HIGH SIDE SWITCH RoHS:否 制造商:Exar 輸出端數量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| ISO1H801GAUMA1 | 制造商:Infineon Technologies AG 功能描述:Power Switch Hi Side 0.625A 36-Pin DSO 制造商:Infineon Technologies AG 功能描述:DRIVER IC - Tape and Reel 制造商:Infineon Technologies AG 功能描述:IC SWITCH HISIDE 8CH DSO-36 |
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