Analog Devices AD215AY Datasheet
120 kHz Bandwidth, Low Distortion,
OUT HI
TRIM
OUT LO
+15V
IN
–15V
IN
PWR RTN
FB
IN–
IN+
IN COM
+V
ISO
–V
ISO
1
3
MODULATOR
37
36
38
42
44
43
6
2
5
4
UNCOMMITTED
INPUT OP AMP
RR
OUTPUT
BUFFER
33kΩ
0.01µF
DEMODULATOR
LOW-PASS
FILTER
150kHz
POWER
ISOLATED
DC
SUPPLY
430kHz
POWER
OSCILLATOR
T1
T2
AD215
SIGNAL
a
FEATURES
Isolation Voltage Rating: 1,500 V rms
Wide Bandwidth: 120 kHz, Full Power (–3 dB)
Rapid Slew Rate: 6 V/ms
Fast Settling Time: 9 ms
Low Harmonic Distortion: –80 dB @ 1 kHz
Low Nonlinearity: 60.005%
Wide Output Range: 610 V, min (Buffered)
Built-in Isolated Power Supply: 615 V dc @ 610 mA
Performance Rated over –408C to +858C
APPLICATIONS INCLUDE
High Speed Data Acquisition Systems
Power Line and Transient Monitors
Multichannel Muxed Input Isolation
Waveform Recording Instrumentation
Power Supply Controls
Vibration Analysis
GENERAL DESCRIPTION
The AD215 is a high speed input isolation amplifier designed to
isolate and amplify wide bandwidth analog signals. The innovative circuit and transformer design of the AD215 ensures wideband dynamic characteristics while preserving key dc performance
specifications.
The AD215 provides complete galvanic isolation between the
input and output of the device including the user-available
front-end isolated power supplies. The functionally complete
design, powered by a ±15 V dc supply, eliminates the need for a
user supplied isolated dc/dc converter. This permits the designer
to minimize circuit overhead and reduce overall system design
complexity and component costs.
The design of the AD215 emphasizes maximum flexibility and
ease of use in a broad range of applications where fast analog
signals must be measured under high common-mode voltage
(CMV) conditions. The AD215 has a ± 10 V input/output
range, a specified gain range of 1 V/V to 10 V/V, a buffered output with offset trim and a user-available isolated front-end
power supply which produces ±15 V dc at ± 10 mA.
PRODUCT HIGHLIGHTS
High Speed Dynamic Characteristics: The AD215 features
a typical full-power bandwidth of 120 kHz (100 kHz min), rise
time of 3 µs and settling time of 9 µs. The high speed perfor-
mance of the AD215 allows for unsurpassed galvanic isolation
of virtually any wideband dynamic signal.
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Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Isolation Amplifier
AD215
FUNCTIONAL BLOCK DIAGRAM
Flexible Input and Buffered Output Stages: An uncommit-
ted op amp is provided on the input stage of the AD215 to
allow for input buffering or amplification and signal conditioning. The AD215 also features a buffered output stage to drive
low impedance loads and an output voltage trim for zeroing the
output offset where needed.
High Accuracy: The AD215 has a typical nonlinearity of
±0.005% (B grade) of full-scale range and the total harmonic
distortion is typically –80 dB at 1 kHz. The AD215 provides
designers with complete isolation of the desired signal without
loss of signal integrity or quality.
Excellent Common-Mode Performance: The AD215BY
(AD215AY) provides 1,500 V rms (750 V rms) common-mode
voltage protection from its input to output. Both grades feature
a low common-mode capacitance of 4.5 pF inclusive of the
dc/dc power isolation. This results in a typical common-mode
rejection specification of 105 dB and a low leakage current of
2.0 µA rms max (240 V rms, 60 Hz).
Isolated Power: An unregulated isolated power supply of
±15 V dc @ ±10 mA is available at the isolated input port of
the AD215. This permits the use of ancillary isolated front-end
amplifiers or signal conditioning components without the need
for a separate dc/dc supply. Even the excitation of transducers
can be accomplished in most applications.
Rated Performance over the –408C to +858C Temperature
Range: With an extended industrial temperature range rating,
the AD215 is an ideal isolation solution for use in many industrial environments.
© Analog Devices, Inc., 1996
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
AD215–SPECIFICA TIONS
(Typical @ +258C, VS = 615 V dc, 2 kV output load, unless otherwise noted.)
AD215AY/BY
Parameter Conditions Min Typ Max Units
GAIN
1
Range
Error G = 1 V/V, No Load on V
ISO
1 10 V/V
±0.5 ±2%
vs. Temperature 0°C to +85°C +15 ppm/°C
–40°C to 0°C +50 ppm/°C
vs. Supply Voltage ±(14.5 V dc to 16.5 V dc) +100 ppm/V
vs. Isolated Supply Load
Nonlinearity
3
2
+20 ppm/mA
AD215BY Grade ±10 V Output Swing, G = 1 V/V ±0.005 ±0.015 %
±10 V Output Swing, G = 10 V/V ±0.01 %
AD215AY Grade ± 10 V Output Swing, G = 1 V/V ±0.01 ± 0.025 %
±10 V Output Swing, G = 10 V/V ±0.025 %
INPUT VOLTAGE RATINGS
Input Voltage Rating G = 1 V/V ±10 V
Maximum Safe Differential Range IN+ or IN–, to IN COM ±15 V
CMRR of Input Op Amp 100 dB
Isolation Voltage Rating
AD215BY Grade 100% Tested
AD215AY Grade 100% Tested
IMRR (Isolation Mode Rejection Ratio) R
4
Input to Output, AC, 60 Hz
≤ 100 Ω (IN+ & IN–), G = 1 V/V, 60 Hz 120 dB
S
R
≤ 100 Ω (IN+ & IN–), G = 1 V/V, 1 kHz 100 dB
S
R
≤ 100 Ω (IN+ & IN–), G = 1 V/V, 10 kHz 80 dB
S
R
≤ 1 kΩ (IN+ & IN–), G = 1 V/V, 60 Hz 105 dB
S
R
≤ 1 kΩ (IN+ & IN–), G = 1 V/V, 1 kHz 85 dB
S
R
≤ 1 kΩ (IN+ & IN–), G = 1 V/V, 10 kHz 65 dB
S
4
4
1500 V rms
750 V rms
Leakage Current, Input to Output 240 V rms, 60 Hz 2 µA rms
INPUT IMPEDANCE
Differential G = 1 V/V 16 MΩ
Common Mode 2i4.5 GΩipF
INPUT OFFSET VOLTAGE
Initial @ +25°C ±0.4 ±2.0 mV
vs. Temperature 0°C to +85°C ±2 µV/°C
–40°C to 0°C ±20 µV/°C
OUTPUT OFFSET VOLTAGE
Initial @ +25°C, Trimmable to Zero 0 –35 –80 mV
vs. Temperature 0°C to +85°C ±30 µV/°C
–40°C to 0°C ±80 µV/°C
vs. Supply Voltage ±350 µV/V
vs. Isolated Supply Load
2
–35 µV/mA
INPUT BIAS CURRENT
Initial @ +25°C 300 nA
vs. Temperature –40°C to +85°C ±400 nA
INPUT DIFFERENCE CURRENT
Initial @ +25°C ±3nA
vs. Temperature –40°C to +85°C ±40 nA
INPUT VOLTAGE NOISE
Input Voltage Noise Frequency > 10 Hz 20 nV/√Hz
DYNAMIC RESPONSE (2 kΩ Load)
Full Signal Bandwidth (–3 dB) G = 1 V/V, 20 V pk-pk Signal 100 120 kHz
Transport Delay
6
2.2 µs
Slew Rate ±10 V Output Swing 6 V/µs
Rise Time 10% to 90%, ±10 V Output Swing 3 µs
–2–
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AD215
AD215AY/BY
Parameter Conditions Min Typ Max Units
DYNAMIC RESPONSE (2 kΩ Load) Cont.
Settling Time to ±0.10%, ±10 V Output Swing 9 µs
Overshoot 1%
Harmonic Distortion Components @ 1 kHz –80 dB
@ 10 kHz –65 dB
Overload Recovery Time G = 1 V/V, ± 15 V Drive 5 µs
Output Overload Recovery Time G > 5 10 µs
RATED OUTPUT
Voltage Out HI to Out LO ±10 V
Current 2 kΩ Load ±5mA
Max Capacitive Load 500 pF
Output Resistance 1 Ω
Output Ripple and Noise
ISOLATED POWER OUTPUT
Voltage No Load ± 14.25 ±15 ±17.25 V
vs. Temperature 0°C to +85°C +20 mV/°C
Current at Rated Supply Voltage
Regulation No Load to Full Load –90 mV/V
Line Regulation 290 mV/V
Ripple 1 MHz Bandwidth, No Load
7
1 MHz Bandwidth 10 mV pk-pk
50 kHz Bandwidth 2.5 mV pk-pk
8
2, 9
–40°C to 0°C +25 mV/°C
±10 mA
2
50 mV rms
POWER SUPPLY
Supply Voltage Rated Performance ±14.5 ±15 ±16.5 V dc
Operating
10
±14.25 ±17 V dc
Current Operating (+15 V dc/–15 V dc Supplies) +40/–18 mA
TEMPERATURE RANGE
Rated Performance –40 +85 °C
Storage –40 +85 °C
NOTES
11
The gain range of the AD215 is specified from 1 to 10 V/V. The AD215 can also be used with gains of up to 100 V/V. With a gain of 100 V/V a 20% reduction in the
–3 dB bandwidth specification occurs and the nonlinearity degrades to ±0.02% typical.
12
When the isolated supply load exceeds ±1 mA, external filter capacitors are required in order to ensure that the gain, offset, and nonlinearity specifications are pre-
served and to maintain the isolated supply full load ripple below the specified 50 mV rms. A value of 6.8 µF is recommended.
13
Nonlinearity is specified as a percent (of full-scale range) deviation from a best straight line.
14
The isolation barrier (and rating) of every AD215 is 100% tested in production using a 5 second partial discharge test with a failure detection threshold of 150 pC. All
“B” grade devices are tested with a minimum voltage of 1,800 V rms. All “A” grade devices are tested with a minimum voltage of 850 V rms.
15
The AD215 should be allowed to warm up for approximately 10 minutes before any gain and/or offset adjustments are made.
16
Equivalent to a 0.8 degrees phase shift.
17
With the ±15 V dc power supply pins bypassed by 2.2 µF capacitors at the AD215 pins.
18
Caution: The AD215 design does not provide short circuit protection of its isolated power supply. A current limiting resistor may be placed in series with the isolated
power terminals and the load in order to protect the supply against inadvertent shorts.
19
With an input power supply voltage greater than or equal ±15 V dc, the AD215 may supply up to ± 15 mA from the isolated power supplies.
10
Voltages less than 14.25 V dc may cause the AD215 to cease operating properly. Voltages greater than ±17.5 V dc may damage the internal components of the
AD215 and consequently should not be used.
Specifications subject to change without notice.
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection.
WARNING!
Although the AD215 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
ESD SENSITIVE DEVICE
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–3–
AD215
IN–
IN+
IN COM
+V
–V
FB
ISO
ISO
4
3
1
2
6
5
UNCOMMITTED
INPUT OP AMP
ISOLATED
SIGNAL
DC
SUPPLY
MODULATOR
DEMODULATOR
T1
POWER
T2
Figure 1. Functional Block Diagram
LOW-PASS
FILTER
150kHz
430kHz
POWER
OSCILLATOR
AD215
R
R
OUTPUT
BUFFER
33kΩ
0.01µF
38
36
37
42
44
43
OUT HI
TRIM
OUT LO
+15V
IN
–15V
IN
PWR RTN
PIN CONFIGURATIONS
1
3
5
4
2
6
BOTTOM VIEW OF
FOOTPRINT
37
36 38
43
44
42
AD215 PIN DESIGNATIONS
Pin Designation Function
1 IN+ Noninverting Input
2 IN COM Input Common
3 IN– Inverting Input
4 FB Amplifier Feedback
5–V
6+V
OUT Isolated –15 V dc Power Supply
ISO
OUT Isolated +15 V dc Power Supply
ISO
36 TRIM Output Offset Trim Adjust
37 OUT LO Output Low
38 OUT HI Output High
42 +15 V
IN
+15 V dc Power
43 PWR RTN ±15 V dc Power Supply Common
44 –15 V
IN
–15 V dc Power
ORDERING GUIDE
Model Temperature Range V
CMV
Nonlinearity
*
AD215AY –40°C to +85°C 750 0.01%
AD215BY –40°C to +85°C 1500 0.005%
*Typical @ +25°C, G = 1 V/V.
INSIDE THE AD215
The AD215 is a fully self-contained analog signal and power
isolation solution. It employs a double-balanced amplitude
modulation technique to perform transformer coupling of signals ranging in frequency from true dc values to those having
frequencies of 120 kHz or less.
To generate the power supplies used for the isolated front-end
circuitry, an internal clock oscillator drives the primary winding
of the integral dc/dc power supply’s transformer, T2. The
resultant voltage developed across the secondary winding is
then rectified and filtered for use as the isolated power supply.
This built-in isolated dc/dc converter provides sufficient power
for both the internal isolated circuit elements of the AD215 as
well as any ancillary components supplied by the user. It saves
onboard space and component cost where additional amplification or signal conditioning is required.
After an input signal is amplified by the uncommitted op amp,
it is modulated at a carrier frequency of approximately 430 kHz
and applied across the primary winding of the signal isolation
transformer T1.
The resultant signal induced on the secondary winding of the
transformer is then demodulated and filtered using a low-pass
Bessel response filter set at a frequency of 150 kHz. The function of the filter reconstructs the original signal as it appears on
the input.
The signal transformer design and construction allow nonlinearity to be independent of both the specified temperature
and gain ranges.
After complete reconstruction, the signal is subjected to an offset trim stage and final output buffer. The trim circuit allows
the designer flexibility to adjust for any offset as desired.
–4–
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