REV. 0
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a
AD260
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700 World Wide Web Site: http://www.analog.com
Fax: 781/326-8703 © Analog Devices, Inc., 1998
High Speed, Logic Isolator
with Power Transformer
FUNCTIONAL BLOCK DIAGRAM
S0
1
F3
21
SYSTEM
FIELD
+5Vdc
5Vdc RTN
DRIVE
+5Vdc
5Vdc RTN
17V p-p OUT
CT OUT
17V p-p OUT
S1
2
S2
3
S3
S4
DRVA
F0
F1
F2
F4
19
20
22
15
16
18
6
7
8
4
5
AD260
+5V
DRVCT
DRIVE
DRVB
TRISTATE
LATCH
E
D
LINE 2
TRISTATE
LATCH
E
D
LINE 1
TRISTATE
LATCH
E
TRISTATE
D
LINE 0
13
14 9
12
10
11
LATCH
D
E
LINE 4
TRISTATE
LATCH
D
E
LINE 3
TRISTATE
+5Vdc
FLD
5V RTN
FLD
ENABLE
FLD
PWRA
FLD
PWRCT
FLD
PWRB
FLD
5V RTN
SYS
+5Vdc
SYS
ENABLE
SYS
17
FEATURES
IsoLogic™ Circuit Architecture
Isolation Test Voltage: To 3.5 kV rms
Five Isolated Logic Lines: Available in Six I/O Configurations
Logic Signal Bandwidth: 20 MHz (Min), 40 mbps (NRZ)
Isolated Power Transformer: 37 V p-p, 1.5 W Max
CMV Transient Immunity: 10 kV/s Min
Waveform Edge Transmission Symmetry: ⴞ1 ns
Field and System Output Enable/Three-State Functions
Performance Rated Over –25ⴗC to +85ⴗC
UL1950, IEC950, EN60950 Certification, Pending
APPLICATIONS
PLC/DCS Analog Input and Output Cards
Communications Bus Isolation
General Data Acquisition Applications
IGBT Motor Drive Controls
High Speed Digital I/O Ports
GENERAL DESCRIPTION
The AD260 is designed using Analog Devices new IsoLogic
circuit architecture to isolate five digital control signals to/
from a microcontroller and its related field I/O components. Six
models allow all I/O combinations from five input lines to five
output lines, including combinations in between. Every AD260
effectively replaces up to five opto-isolators while also providing
the 1.5 W transformer for a 3.5 kV isolated dc-dc power supply
circuit.
Each line of the AD260 has a bandwidth of 20 MHz (min) with
a propagation delay of only 14 ns, which allows for extremely
fast data transmission. Output waveform symmetry is maintained
to within ±1 ns of the input so the AD260 can be used to accu-
rately isolate time-based PWM signals.
All field or system output pins of the AD260 can be set to a high
resistance three-state level by use of the two enable pins. A field
output three-stated offers a convenient method of presetting
logic levels at power-up by use of pull-up/down resistors. Sys-
tem side outputs being three-stated allows for easy multiplexing
of multiple AD260s.
The isolation barrier of the AD260 B Grade is 100% tested at
3.5 kV rms (system to field). The barrier design also provides
excellent common-mode transient immunity from 10 kV/µs
common-mode voltage excursions of field side terminals relative
to the system side, with no false output triggering on either side.
Each output is updated within nanoseconds by input logic tran-
sitions, the AD260 also has a continuous output update feature
that automatically updates each output based on the dc level of
the input. This guarantees the output is always valid 10 µs after
a fault condition or after the power-up reset interval.
The AD260 also has an integral center tap transformer for gen-
erating isolated power. Typically driven by a 5 V push-pull drive
at the primary, it will generate a 37 V p-p output capable of
supplying up to 1.5 W. This can then be regulated to the de-
sired voltage, including ±5 V dc for circuit components and
24 V for a 20 mA loop supply when needed.
PRODUCT HIGHLIGHTS
Six Isolated Logic Line I/O Configurations Available: The
AD260 is available in six pin-compatible versions of I/O con-
figurations to meet a wide variety of requirements.
Wide Bandwidth with Minimal Edge Error: The AD260 with
IsoLogic affords extremely fast isolation of logic signals due to its
20 MHz bandwidth and 14 ns propagation delay. It maintains a
waveform input-to-output edge transition error of typically less
than ±1 ns (total) for positive vs. negative transition.
3.5 kV rms Test Voltage Isolation Rating: The AD260
B Grade is rated to operate at 1.25 kV rms and is 100% pro-
duction tested at 3.5 kV rms, using a standard ADI test method.
High Transient Immunity: The AD260 rejects common-
mode transients slewing at up to 10 kV/µs without false trigger-
ing or damage to the device.
(Continued on page 6)
IsoLogic is a trademark of Analog Devices, Inc.
