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參數(shù)資料
| 型號(hào)： | ISO164 |
| 英文描述： | Precision, Isolated PROGRAMMABLE GAIN AMPLIFIER |
| 中文描述： | 精密，隔離可編程增益放大器 |
| 文件頁(yè)數(shù)： | 7/8頁(yè) |
| 文件大小： | 194K |
| 代理商： | ISO164 |
7
ISO164/ISO174
The ideal external clock signal for the ISO164 and ISO174
is a
±
4V sine wave or
±
4V, 50% duty-cycle triangle wave.
The Ext Osc pin of the ISO164 and ISO174 can be driven
directly with a
±
3V to
±
5V sine or 25% to 75% duty-cycle
triangle wave and the ISO amp’s internal modulator/de-
modulator circuitry will synchronize to the signal.
ISO174 can also be synchronized to a 400kHz to 700kHz
Square-Wave External Clock since an internal clamp and
filter provide signal conditioning. A square-wave signal of
25% to 75% duty cycle, and
±
3V to
±
20V level can be used
to directly drive the ISO174.
With the addition of the signal conditioning circuit shown in
Figure 2, any 10% to 90% duty-cycle square-wave signal
can be used to drive the ISO164 and ISO174 Ext Osc pin.
With the values shown, the circuit can be driven by a
4Vp-p TTL signal. For a higher or lower voltage input,
increase or decrease the 1k
resistor, R
X
, proportionally,
e.g., for a
±
4V square-wave (8Vp-p) R
X
should be increased
to 2k
. The value of C
X
used in the Figure 2 circuit depends
on the frequency of the external clock signal. C
X
should be
30pF for ISO174 and 680pF for ISO164.
under these circumstances unless the input signal contains
significant components above 250kHz.
For the ISO164, the carrier frequency is nominally 110kHz
and the –3dB point of the amplifier is 6kHz.
When periodic noise from external sources such as system
clocks and DC/DC converters are a problem, ISO164 and
ISO174 can be used to reject this noise. The amplifier can be
synchronized to an external frequency source, f
EXT
, placing
the amplifier response curve at one of the frequency and
amplitude nulls indicated in the “Signal Response vs Carrier
Frequency” performance curve. Figure 3 shows circuitry
with opto-isolation suitable for driving the Ext Osc input
from TTL levels.
CARRIER FREQUENCY CONSIDERATIONS
ISO164 and ISO174 amplifiers transmit the signal across the
ISO-barrier by a duty-cycle modulation technique. This
system works like any linear amplifier for input signals
having frequencies below one half the carrier frequency, f
C
.
For signal frequencies above f
C
/2, the behavior becomes
more complex. The “Signal Response vs Carrier Frequency”
performance curve describes this behavior graphically. The
upper curve illustrates the response for input signals varying
from DC to f
C
/2. At input frequencies at or above f
C
/2, the
device generates an output signal component that varies in
both amplitude and frequency, as shown by the lower curve.
The lower horizontal scale shows the periodic variation in
the frequency of the output component. Note that at the
carrier frequency and its harmonics, both the frequency and
amplitude of the response go to zero. These characteristics
can be exploited in certain applications.
It should be noted that for the ISO174, the carrier frequency
is nominally 500kHz and the –3dB point of the amplifier is
60kHz. Spurious signals at the output are not significant
ISOLATION MODE VOLTAGE
Isolation Mode Voltage (IMV) is the voltage appearing
between isolated grounds GND 1 and GND 2. The IMV can
induce errors at the output as indicated by the plots of IMV
vs Frequency. It should be noted that if the IMV frequency
exceeds f
C
/2, the output will display spurious outputs in a
manner similar to that described above, and the amplifier
response will be identical to that shown in the “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 ISO164 and ISO174 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
FIGURE 2. Square-Wave to Triangle Wave Signal Condi-
tioner for Driving ISO164/174 Ext Osc Pin.
10k
C
X
OPA602
R
X
1μF
Sq Wave In
Triangle Out
to ISO164/174
Ext Osc
1k
FIGURE 3. Synchronization with Isolated Drive Circuit for
Ext Osc Pin.
C
1
Ext Osc
Pin 21
ISO164/174
C
2
10k
6
5
8
2
3
TTL
f
IN
2.5k
200
+15V
+5V
IN
(
)
C
1
= 140E-6
C
2
= 10 x C
1
, with a minimum 10nF
2.5k
6N136
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISO165 | Precision Instrumentation Amplifier |
| 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 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISO164/ISO174 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:ISO164. ISO174 - DISCONTINUED PRODUCT. No longer recommended for new design. |
| ISO165 | 制造商:BB 制造商全稱(chēng):BB 功能描述:INSTRUMENTATION AMPLIFIER |
| ISO165/ISO175 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:ISO165. ISO175 - DISCONTINUED PRODUCT. No longer recommended for new design. |
| ISO166 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述: |
| ISO166/ISO176 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:ISO166. ISO176 - DISCONTINUED PRODUCT. No longer recommended for new design. |
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