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參數資料
| 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： | 7/8頁 |
| 文件大小： | 164K |
| 代理商： | ISO165 |
7
ISO165/ISO175
overloaded, the protection circuitry limits the input current
to a safe value of approximately 1.5 to 5mA. The inputs are
protected even if the power supplies are disconnected or
turned off.
SYNCHRONIZED OPERATION
ISO165 and ISO175 can be synchronized to an external
signal source. This capability is useful in eliminating trouble-
some beat frequencies in multichannel systems and in reject-
ing AC signals and their harmonics. To use this feature, an
external signal must be applied to the Ext Osc pin. ISO165
can be synchronized over the 100kHz to 200kHz range and
ISO175 can be synchronized over the 400kHz to 700kHz
range.
The ideal external clock signal for the ISO165 and ISO175
is a
±
4V sine wave or
±
4V, 50% duty-cycle triangle wave.
The Ext Osc pin of the ISO165 and ISO175 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.
ISO175 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 ISO175.
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 ISO165 and ISO175 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 ISO175 and 680pF for ISO165.
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 ISO175, the carrier frequency
is nominally 500kHz and the –3dB point of the amplifier is
60kHz. Spurious signals at the output are not significant
under these circumstances unless the input signal contains
significant components above 250kHz.
For the ISO165, 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, ISO165 and
ISO175 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 fre-
quency and amplitude nulls indicated in the “Signal Re-
sponse vs Carrier Frequency” performance curve. Figure 3
shows circuitry with opto-isolation suitable for driving the
Ext Osc input from TTL levels.
10k
C
X
OPA602
R
X
1μF
Sq Wave In
Triangle Out
to ISO165/175
Ext Osc
1k
FIGURE 2. Square-Wave to Triangle Wave Signal Condi-
tioner for Driving ISO165/175 Ext Osc Pin.
CARRIER FREQUENCY CONSIDERATIONS
ISO165 and ISO175 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
ISOLATION MODE VOLTAGE
Isolation Mode Voltage (IMV) is the voltage appearing
between isolated grounds GND1 and GND2. The IMV can
induce errors at the output as indicated by the plots of IMV
versus Frequency. It should be noted that if the IMV fre-
quency exceeds f
C
/2, the output will display spurious out-
puts in a manner similar to that described above, and the
amplifier response will be identical to that shown in the
C
1
Ext Osc on
ISO165/ISO175
(Pin 21)
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
FIGURE 3. Synchronization with Isolated Drive Circuit for
Ext Osc Pin.
相關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 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| 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 相關繼電器系列:RP, RT, RY 端接類型:PCB 極數:1 |
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