AD202 Fast Delivery |IC PHOENIX CO.,LIMITED

AD202 ,Low Cost, Miniature Isolation Amplifiers Powered Directly From a +15 V DC Supplyapplications where input signals must be measured,cations like control loops, where limited bandwid ..
AD202JN ,Low Cost, Miniature Isolation AmplifiersSPECIFICATIONS SModel AD204J AD204K AD202J AD202KGAINRange 1 V/V–100 V/V * * *Error ±0.5% typ (±4% ..
AD202JY ,Low Cost, Miniature Isolation AmplifiersGENERAL DESCRIPTIONand low drift over temperature, the AD202 and AD204 provideThe AD202 and AD204 a ..
AD202KN ,Low Cost, Miniature Isolation AmplifiersGENERAL DESCRIPTIONand low drift over temperature, the AD202 and AD204 provideThe AD202 and AD204 a ..
AD202KY ,Low Cost, Miniature Isolation AmplifiersSpecifications same as AD204J.1Nonlinearity is specified as a % deviation from a best straight line ..
AD203SN ,Rugged, Military Temperature Range, 10 kHz Bandwidth Isolation AmplifierSPECIFICATIONS (typical @ +NT, ll, = +15 ll d/ses, 5therwise noted) GAIN Range Error vs. Temp ..
AD8402ARZ10-REEL , 1-/2-/4-Channel Digital Potentiometers
AD8403 ,4-Channel Digital PotentiometerCHARACTERISTICSBandwidth –3 dB BW_10K R = 10 kΩ 600 kHzTotal Harmonic Distortion THD V = 1 V rms + ..
AD8403AN10 ,1-/2-/4-Channel Digital PotentiometersSpecifications Apply to All VRsResolution N 8 Bits4Integral Nonlinearity INL –4 ±1 +4 LSB4Different ..
AD8403AN100 ,1-/2-/4-Channel Digital PotentiometersSpecifications Apply to All VRs2Resistor Differential NL R-DNL R , V = NC –1 ±1/4 +1 LSBWB A2Resist ..
AD8403AN50 ,1-/2-/4-Channel Digital PotentiometersSpecifications Apply to All VRs2Resistor Differential NL R-DNL R , V = NC –1 ±1/4 +1 LSBWB A2Resist ..
AD8403AR1 ,1-/2-/4-Channel Digital PotentiometersCHARACTERISTICSBandwidth –3 dB BW_10K R = 10 kΩ 600 kHzTotal Harmonic Distortion THD V = 1 V rms + ..

AD202
Low Cost, Miniature Isolation Amplifiers Powered Directly From a +15 V DC Supply
REV.D
Low Cost, Miniature
Isolation Amplifiers
FEATURES
Small Size: 4 Channels/lnch
Low Power: 35 mW (AD204)
High Accuracy: �0.025% Max Nonlinearity (K Grade)
High CMR: 130 dB (Gain = 100 V/V)
Wide Bandwidth: 5 kHz Full-Power (AD204)
High CMV Isolation: �2000 V pk Continuous (K Grade)
(Signal and Power)
Isolated Power Outputs
Uncommitted Input Amplifier
APPLICATIONS
Multichannel Data Acquisition
Current Shunt Measurements
Motor Controls
Process Signal Isolation
High Voltage Instrumentation Amplifier
GENERAL DESCRIPTION
The AD202 and AD204 are general purpose, two-port, trans-
former-coupled isolation amplifiers that may be used in a broad
range of applications where input signals must be measured,
processed, and/or transmitted without a galvanic connection.
These industry standard isolation amplifiers offer a complete
isolation function, with both signal and power isolation provided
for in a single compact plastic SIP or DIP style package. The
primary distinction between the AD202 and the AD204 is that
the AD202 is powered directly from a 15 V dc supply while the
AD204 is powered by an externally supplied clock, such as the
recommended AD246 Clock Driver.
The AD202 and AD204 provide total galvanic isolation between
the input and output stages of the isolation amplifier through
the use of internal transformer-coupling. The functionally com-
plete AD202 and AD204 eliminate the need for an external,
user-supplied dc-to-dc converter. This permits the designer
to minimize the necessary circuit overhead and consequently
reduce the overall design and component costs.
The design of the AD202 and AD204 emphasizes maximum
flexibility and ease of use, including the availability of an
uncommitted op amp on the input stage. They feature a bipolar±5 V output range, an adjustable gain range of from 1V/V to
100 V/V, ±0.025% max nonlinearity (K grade), 130 dB of
CMR, and the AD204 consumes a low 35 mW of power.
The functional block diagrams can be seen in Figures 1a and 1b.
PRODUCT HIGHLIGHTS
The AD202 and AD204 are full-featured isolators offering
numerous benefits to the user:
Small Size: The AD202 and AD204 are available in SIP and
DIP form packages. The SIP package is just 0.25" wide, giving
the user a channel density of four channels per inch. The isolation
barrier is positioned to maximize input to output spacing. For
applications requiring a low profile, the DIP package provides a
height of just 0.350".
High Accuracy:With a maximum nonlinearity of ±0.025%
for the AD202K/AD204K (±0.05% for the AD202J/AD204J)
and low drift over temperature, the AD202 and AD204 provide
high isolation without loss of signal integrity.
Low Power:Power consumption of 35 mW (AD204) and
75 mW (AD202) over the full signal range makes these isolators
ideal for use in applications with large channel counts or tight
power budgets.
Wide Bandwidth:The AD204’s full-power bandwidth of 5kHz
makes it useful for wideband signals. It is also effective in appli-
cations like control loops, where limited bandwidth could result
in instability.
Excellent Common-Mode Performance:The AD202K/
AD204K provide ±2000 V pk continuous common-mode isola-
tion, while the AD202J/AD204J provide ±1000 V pk continuous
common-mode isolation. All models have a total common-mode
input capacitance of less than 5 pF inclusive of power isolation.
This results in CMR ranging from 130 dB at a gain of 100 dB to
104 dB (minimum at unity gain) and very low leakage current
(2 mA maximum).
Flexible Input:An uncommitted op amp is provided at the
input of all models. This provides buffering and gain as required,
and facilitates many alternative input functions including filtering,
summing, high voltage ranges, and current (transimpedance) input.
Isolated Power:The AD204 can supply isolated power of±7.5 V at 2 mA. This is sufficient to operate a low-drift input
preamp, provide excitation to a semiconductor strain gage, or
power any of a wide range of user-supplied ancillary circuits.
The AD202 can supply ±7.5 V at 0.4 mA, which is sufficient to
operate adjustment networks or low power references and op
amps, or to provide an open-input alarm.
AD202/AD204–SPECIFICATIONS
INPUT VOLTAGE RATINGS
INPUT BIAS CURRENT
INPUT DIFFERENCE CURRENT
INPUT NOISE
OFFSET VOLTAGE (RTI)
RATED OUTPUT
OSCILLATOR DRIVE INPUT
POWER SUPPLY (AD202 Only)
(Typical @ 25�C and VS = 15 V unless otherwise noted.)
AD246–SPECIFICATIONS
(Typical @ 25∞C and VS = 15 V unless otherwise noted.)
NOTES
*Specifications the same as the AD246JY.The high current drive output will not support a short to ground.
Specifications subject to change without notice.
AD246 Pin Designations
Pin (Y)
ORDERING GUIDE
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD202/AD204 features proprietary ESD protection circuitry, permanent damage may occur on
devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are
PIN DESIGNATIONS
AD202/AD204 SIP Package
AD202/AD204 DIP Package
AD202/AD204
DIFFERENCES BETWEEN THE AD202 AND AD204
The primary distinction between the AD202 and AD204 is in
the method by which they are powered: the AD202 operates
directly from 15 V dc while the AD204 is powered by a non-
isolated externally-supplied clock (AD246) that can drive up to
32 AD204s. The main advantages of using the externally-
clocked AD204 over the AD202 are reduced cost in multichannel
applications, lower power consumption, and higher bandwidth.
In addition, the AD204 can supply substantially more isolated
power than the AD202.
Of course, in a great many situations, especially where only one
or a few isolators are used, the convenience of standalone opera-
tion provided by the AD202 will be more significant than any
of the AD204’s advantages. There may also be cases where it is
desirable to accommodate either device interchangeably, so the
pinouts of the two products have been designed to make that
easy to do.
Figure 1a.AD202 Functional Block Diagram
Figure 1b.AD204 Functional Block Diagram
(Pin Designations Apply to the DIP-Style Package)
INSIDE THE AD202 AND AD204
The AD202 and AD204 use an amplitude modulation technique
to permit transformer coupling of signals down to dc (Figure 1a
and 1b). Both models also contain an uncommitted input op
amp and a power transformer that provides isolated power to
the op amp, the modulator, and any external load. The power
transformer primary is driven by a 25 kHz, 15 V p-p square
wave generated internally in the case of the AD202, or supplied
externally for the AD204.
Within the signal swing limits of approximately ±5 V, the out-
put voltage of the isolator is equal to the output voltage of the
op amp; that is, the isolation barrier has unity gain. The output
signal is not internally buffered, so the user is free to interchange
the output leads to get signal inversion. Additionally, in multi-
channel applications, the unbuffered outputs can be multiplexed
with one buffer following the mux. This technique minimizes
offset errors while reducing power consumption and cost. The
output resistance of the isolator is typically 3 kΩ for the AD204
(7 kΩ for AD202) and varies with signal level and temperature,
so it should not be loaded (see Figure 2 for the effects of load
upon nonlinearity and gain drift). In many cases, a high imped-
ance load will be present or a following circuit such as an output
filter can serve as a buffer so that a separate buffer function will
not often be needed.
OUTPUT LOAD – M�
GAIN
CHANGE
(%)
GAIN TC
CHANGE
(ppm/�C)
NON-
LINEARITY
(%)
Figure 2.Effects of Output Loading
USING THE AD202 AND AD204
Powering the AD202. The AD202 requires only a single 15 V
power supply connected as shown in Figure 3a. A bypass capaci-
tor is provided in the module.
Figure 3a.
Powering the AD204. The AD204 gets its power from an
externally supplied clock signal (a 15 V p-p square wave with a
nominal frequency of 25 kHz) as shown in Figure 3b.
Figure 3b.
AD246 Clock Driver. The AD246 is a compact, inexpensive
clock driver that can be used to obtain the required clock from a
single 15 V supply. Alternatively, the circuit shown in Figure 4
(essentially an AD246) can be used. In either case, one clock
circuit can operate at least 32 AD204s at the rated minimum
supply voltage of 14.25 V and one additional isolator can be
operated for each 40 mV increase in supply voltage up to 15 V.
A supply bypass capacitor is included in the AD246, but if many
AD204s are operated from a single AD246, an external bypass
capacitor should be used with a value of at least 1 mF for every
five isolators used. Place the capacitor as close as possible to the
clock driver.
Figure 4.Clock Driver
Input Configurations. The AD202 and AD204 have been
designed to be very easy to use in a wide range of applications.
The basic connection for standard unity gain applications, useful
for signals up to ±5 V, is shown in Figure 5; some of the possible
variations are described below. When smaller signals must be
handled, Figure 6 shows how to achieve gain while preserving a
very high input resistance. The value of feedback resistor RF
should be kept above 20 kW for best results. Whenever a gain of
more than five is taken, a 100 pF capacitor from FB to IN COM
is required. At lower gains this capacitor is unnecessary, but it
will not adversely affect performance if used.
Figure 5.Basic Unity-Gain Application
Figure 6.Input Connections for Gain > 1
The noninverting circuit of Figures 5 and 6 can also be used to
your advantage when a signal inversion is needed: just interchange
either the input leads or the output leads to get inversion. This
approach retains the high input resistance of the noninverting
circuit, and at unity gain no gain-setting resistors are needed.
When the isolator is not powered, a negative input voltage of
more than about 2 V will cause an input current to flow. If the
signal source can supply more than a few mA under such con-
ditions, the 2 kW resistor shown in series with IN+ should be
used to limit current to a safe value. This is particularly impor-
tant with the AD202, which may not start if a large input current
is present.
Figure 7 shows how to accommodate current inputs or sum
currents or voltages. This circuit can also be used when the
input signal is larger than the ±5 V input range of the isolator;
for example, a ±50 V input span can be accommodated with
RF = 20 kW and RS = 200 kW. Once again, a capacitor from FB
to IN COM is required for gains above five.
Figure 7.Connections for Summing or Current Inputs
AD202/AD204
Adjustments. When gain and zero adjustments are needed, the
circuit details will depend on whether adjustments are to be made
at the isolator input or output, and (for input adjustments) on
the input circuit used. Adjustments are usually best done on the
input side, because it is better to null the zero ahead of the gain,
and because gain adjustment is most easily done as part of the
gain-setting network. Input adjustments are also to be preferred
when the pots will be near the input end of the isolator (to mini-
mize common-mode strays). Adjustments on the output side
might be used if pots on the input side would represent a hazard
due to the presence of large common-mode voltages during
adjustment.
Figure 8a shows the input-side adjustment connections for use
with the noninverting connection of the input amplifier. The
zero adjustment circuit injects a small adjustment voltage in series
with the low side of the signal source. (This will not work if the
source has another current path to input common or if current
flows in the signal source LO lead). Since the adjustment volt-
age is injected ahead of the gain, the values shown will work for
any gain. Keep the resistance in series with input LO below a
few hundred ohms to avoid CMR degradation.
Figure 8a. Adjustments for Noninverting Connection of
Op Amp
Also shown in Figure 8a is the preferred means of adjusting the
gain-setting network. The circuit shown gives a nominal RF of
50 kW, and will work properly for gains of ten or greater. The
adjustment becomes less effective at lower gains (its effect is
halved at G = 2) so that the pot will have to be a larger fraction
of the total RF at low gain. At G = 1 (follower) the gain cannot
be adjusted downward without compromising input resistance;
it is better to adjust gain at the signal source or after the output.
Figure 8b shows adjustments for use with inverting input cir-
cuits. The zero adjustment nulls the voltage at the summing
node. This method is preferable to current injection because it is
less affected by subsequent gain adjustment. Gain adjustment is
again done in the feedback; but in this case it will work all the
way down to unity gain (and below) without alteration.
Figure 8b.Adjustments for Summing or Current Input
Figure 9 shows how zero adjustment is done at the output by
taking advantage of the semi-floating output port. The range of
this adjustment will have to be increased at higher gains; if that
is done, be sure to use a suitably stable supply voltage for the
pot circuit.
There is no easy way to adjust gain at the output side of the
isolator itself. If gain adjustment must be done on the output
side, it will have to be in a following circuit such as an output
buffer or filter.
Figure 9.Output-Side Zero Adjustment
Common-Mode Performance.Figures 10a and 10b show
how the common-mode rejection of the AD202 and AD204
varies with frequency, gain, and source resistance. For these
isolators, the significant resistance will normally be that in the
path from the source of the common-mode signal to IN COM.
The AD202 and AD204 also perform well in applications re-
quiring rejection of fast common-mode steps, as described in
the Applications section.

Partno	Mfg	Dc	Qty	Available	Descript
AD202	AD	N/a	2	avai	Low Cost, Miniature Isolation Amplifiers Powered Directly From a +15 V DC Supply