Signal and Power Isolated RS-
485
Transceiver with ±15 kV ESD Protection
Data Sheet
ADM2582E/ADM2587E
Rev. G Document Feedback
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FEATURES
Isolated RS-485/RS-422 transceiver, configurable as half or
full duplex
isoPower integrated isolated dc-to-dc converter
±15 kV ESD protection on RS-485 input/output pins
Complies with ANSI/TIA/EIA-485-A-98 and ISO 8482:1987(E)
ADM2582E data rate: 16 Mbps
ADM2587E data rate: 500 kbps
5 V or 3.3 V operation
Connect up to 256 nodes on one bus
Open- and short-circuit, fail-safe receiver inputs
High common-mode transient immunity: >25 kV/µs
Thermal shutdown protection
Safety and regulatory approvals
UL recognition: 2500 V rms for 1 minute per UL 1577
VDE Certificates of Conformity
DIN EN 60747-5-2 (VDE 0884 Part 2): 2003-01
VIORM = 560 V peak
Operating temperature range: 40°C to +85°C
Highly integrated, 20-lead, wide-body SOIC package
APPLICATIONS
Isolated RS-485/RS-422 interfaces
Industrial field networks
Multipoint data transmission systems
FUNCTIONAL BLOCK DIAGRAM
ADM2582E/ADM2587E
TxD
A
B
Y
Z
DE
V
CC
RxD
RE
ISOLATION
BARRIER
TRANSCEIVER
GND
1
GND
2
ENCODE
ENCODE
DECODE
DECODE D
R
DECODE
ENCODE
OSCILLATOR RECTIFIER
REGULATOR
V
ISOOUT
DIGITAL ISOLATION iCoupler
isoPower DC-TO-DC CONVERTER
V
ISOIN
08111-001
Figure 1.
GENERAL DESCRIPTION
The ADM2582E/ADM2587E are fully integrated signal and
power isolated data transceivers with ±15 kV ESD protection
and are suitable for high speed communication on multipoint
transmission lines. The ADM2582E/ADM2587E include an
integrated isolated dc-to-dc power supply, which eliminates the
need for an external dc-to-dc isolation block.
They are designed for balanced transmission lines and comply
with ANSI/TIA/EIA-485-A-98 and ISO 8482:1987(E).
The devices integrate Analog Devices, Inc., iCoupler® technology
to combine a 3-channel isolator, a three-state differential line driver,
a differential input receiver, and Analog Devices isoPower® dc-to-
dc converter into a single package. The devices are powered by a
single 5 V or 3.3 V supply, realizing a fully integrated signal and
power isolated RS-485 solution.
The ADM2582E/ADM2587E driver has an active high enable.
An active low receiver enable is also provided, which causes the
receiver output to enter a high impedance state when disabled.
The devices have current limiting and thermal shutdown
features to protect against output short circuits and situations
where bus contention may cause excessive power dissipation.
The parts are fully specified over the industrial temperature
range and are available in a highly integrated, 20-lead, wide-body
SOIC package.
The ADM2582E/ADM2587E contain isoPower technology that
uses high frequency switching elements to transfer power through
the transformer. Special care must be taken during printed circuit
board (PCB) layout to meet emissions standards. Refer to the
AN-0971 Application Note, Control of Radiated Emissions with
isoPower Devices, for details on board layout considerations.
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 2 of 22
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 4
ADM2582E Timing Specifications ............................................ 5
ADM2587E Timing Specifications ............................................ 5
ADM2582E/ADM2587E Package Characteristics ................... 5
ADM2582E/ADM2587E Regulatory Information .................. 6
ADM2582E/ADM2587E Insulation and Safety-Related
Specifications ................................................................................ 6
ADM2582E/ADM2587E VDE 0884 Insulation
Characteristics .............................................................................. 6
Absolute Maximum Ratings ............................................................ 7
ESD Caution .................................................................................. 7
Pin Configuration and Function Descriptions ............................. 8
Typical Performance Characteristics ............................................. 9
Test Circuits ..................................................................................... 13
Switching Characteristics .............................................................. 14
Circuit Description......................................................................... 15
Signal Isolation ........................................................................... 15
Power Isolation ........................................................................... 15
Truth Tables................................................................................. 15
Thermal Shutdown .................................................................... 15
Open- and Short-Circuit, Fail-Safe Receiver Inputs.............. 15
DC Correctness and Magnetic Field Immunity ........................... 15
Applications Information .............................................................. 17
PCB Layout and Electromagnetic Interference (EMI) .......... 17
Insulation Lifetime ..................................................................... 18
Isolated Power Supply Considerations .................................... 19
Typical Applications ................................................................... 20
Outline Dimensions ....................................................................... 22
Ordering Guide .......................................................................... 22
REVISION HISTORY
5/2018—Rev. F to Rev. G
Changes to Table 10 .......................................................................... 8
Deleted Electromagnetic Interference (EMI) Considerations
Section .............................................................................................. 16
Changes to PCB Layout and Electromagnetic Interference
(EMI) Section .................................................................................. 17
Changes to Figure 35 ...................................................................... 18
Changes to PCB Layout Reference ............................................... 19
Changes to Ordering Guide .......................................................... 22
9/2016—Rev. E to Rev. F
Changes to Ordering Guide .......................................................... 20
10/2014—Rev. D to Rev. E
Changes to Table 12 ........................................................................ 14
9/2014—Rev. C to Rev. D
Changes to Figure 9 .......................................................................... 9
6/2011—Rev. B to Rev. C
Changes to Features Section and Figure 1 ..................................... 1
Changes to Table 4 ............................................................................. 4
Changes to Table 5 ............................................................................. 5
Deleted Table 6; Renumbered Sequentially ................................... 5
Added Thermal Resistance θJA Parameter, Table 8 ....................... 6
Changes to Table 9 ............................................................................. 6
Changes to Table 10 .......................................................................... 7
Changes to Table 13 ....................................................................... 14
Moved DC Correctness and Magnetic Field Immunity
Sec tion .............................................................................................. 14
Changes to PCB Layout Section and Figure 35 .......................... 16
Changes to Figure 39 ...................................................................... 17
Changes to Typical Applications Section and Figure 40 ........... 18
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 3 of 22
3/2011Rev. A to Rev. B
Removed Pending from Safety and Regulatory
Approvals ........................................................................ Throughout
Changed Minimum External Air Gap (Clearance) Value and
Minimum External Tracking (Creepage) Value ............................ 5
Added Text to the ADM2582E/ADM2587E VDE 0884
Insulation Characteristics Section ................................................. 5
9/2010Rev. 0 to Rev. A
Changes to Features Section ............................................................ 1
Changes to Differential Output Voltage, Loaded Parameter,
Table 1 ................................................................................................. 3
Changes to Table 5 ............................................................................ 5
Added Table 6; Renumbered Sequentially ..................................... 5
Change to Pin 8 Description, Table 11 ........................................... 7
Changes to Figure 5 and Figure 6 ................................................... 8
Changes to Table 13 and Table 14 ................................................. 14
9/2009—Revision 0: Initial Version
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 4 of 22
SPECIFICATIONS
All voltages are relative to their respective ground; 3.0 ≤ VCC 5.5 V. All minimum/maximum specifications apply over the entire
recommended operation range, unless otherwise noted. All typical specifications are at TA = 25°C, VCC = 5 V unless otherwise noted.
Table 1.
Parameter Symbol Min Typ Max Unit Test Conditions
ADM2587E SUPPLY CURRENT ICC
Data Rate ≤ 500 kbps 90 mA VCC = 3.3 V, 100 Ω load between Y and
Z
72 mA VCC = 5 V, 100 Ω load between Y and Z
125 mA VCC = 3.3 V, 54 Ω load between Y and
Z
98 mA VCC = 5 V, 54 Ω load between Y and Z
120 mA 120 Ω load between Y and Z
ADM2582E SUPPLY CURRENT
I
CC
Data Rate = 16 Mbps 150 mA 120 Ω load between Y and Z
230 mA 54 Ω load between Y and Z
ISOLATED SUPPLY VOLTAGE
V
ISOUT
DRIVER
Differential Outputs
Differential Output Voltage, Loaded |VOD2| 2.0 3.6 V RL = 100 Ω (RS-422), see Figure 23
1.5 3.6 V RL = 54 Ω (RS-485), see Figure 23
|VOD3| 1.5 3.6 V −7 V ≤ VTEST1 ≤ 12 V, see Figure 24
Δ|VOD| for Complementary Output States Δ|VOD| 0.2 V RL = 54 Ω or 100 Ω, see Figure 23
Common-Mode Output Voltage VOC 3.0 V RL = 54 Ω or 100 Ω, see Figure 23
Δ|VOC| for Complementary Output States Δ|VOC| 0.2 V RL = 54 Ω or 100 Ω, see Figure 23
Short-Circuit Output Current IOS 200 mA
Output Leakage Current (Y, Z) IO 30 µA DE = 0 V, RE = 0 V, VCC = 0 V or 3.6 V,
VIN = 12 V
30 µA DE = 0 V, RE = 0 V, VCC = 0 V or 3.6 V,
VIN = −7 V
Logic Inputs DE, RE, TxD
Input Threshold Low VIL 0.3 × VCC V DE, RE, TxD
Input Threshold High VIH 0.7 × VCC V DE, RE, TxD
Input Current II −10 0.01 10 µA DE, RE, TxD
RECEIVER
Differential Inputs
Differential Input Threshold Voltage VTH −200 125 −30 mV −7 V < VCM < +12 V
Input Voltage Hysteresis VHYS 15 mV VOC = 0 V
Input Current (A, B) II 125 µA DE = 0 V, VCC = 0 V or 3.6 V, VIN = 12 V
−100 µA DE = 0 V, VCC = 0 V or 3.6 V, VIN = 7 V
Line Input Resistance RIN 96 kΩ −7 V < VCM < +12 V
Logic Outputs
Output Voltage Low VOL 0.2 0.4 V IO = 1.5 mA, VA − VB = −0.2 V
Output Voltage High VOH VCC − 0.3 VCC − 0.2 V IO = −1.5 mA, VA − VB = 0.2 V
Short-Circuit Current
100
mA
COMMON-MODE TRANSIENT IMMUNITY1 25 kV/µs VCM = 1 kV, transient magnitude = 800 V
1 CM is the maximum common-mode voltage slew rate that can be sustained while maintaining specification-compliant operation. VCM is the common-mode potential
difference between the logic and bus sides. The transient magnitude is the range over which the common-mode is slewed. The common-mode voltage slew rates
apply to both rising and falling common-mode voltage edges.
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 5 of 22
ADM2582E TIMING SPECIFICATIONS
TA = −40°C to +85°C.
Table 2.
Parameter Symbol Min Typ Max Unit Test Conditions
DRIVER
Maximum Data Rate 16 Mbps
Propagation Delay, Low to High tDPLH 63 100 ns RL = 54 Ω, CL1 = C L2 = 100 pF, see Figure 25 and Figure 29
Propagation Delay, High to Low tDPHL 64 100 ns RL = 54 Ω, CL1 = C L2 = 100 pF, see Figure 25 and Figure 29
Output Skew tSKEW 1 8 ns RL = 54 Ω, CL1 = CL2 = 100 pF, see Figure 25 and Figure 29
Rise Time/Fall Time tDR, tDF 15 ns RL = 54 Ω, CL1 = CL2 = 100 pF, see Figure 25 and Figure 29
Enable Time tZL, tZH 120 ns RL = 110 , CL = 50 pF, see Figure 26 and Figure 31
Disable Time tLZ, tHZ 150 ns RL = 110 , CL = 50 pF, see Figure 26 and Figure 31
RECEIVER
Propagation Delay, Low to High tRPLH 94 110 ns CL = 15 pF, see Figure 27 and Figure 30
Propagation Delay, High to Low tRPHL 95 110 ns CL = 15 pF, see Figure 27 and Figure 30
Output Skew1 tSKEW 1 12 ns CL = 15 pF, see Figure 27 and Figure 30
Enable Time tZL, tZH 15 ns RL = 1 k, CL = 15 pF, see Figure 28 and Figure 32
Disable Time tLZ, tHZ 15 ns RL = 1 k, CL = 15 pF, see Figure 28 and Figure 32
1 Guaranteed by design.
ADM2587E TIMING SPECIFICATIONS
TA = −40°C to +85°C.
Table 3.
Parameter Symbol Min Typ Max Unit Test Conditions
DRIVER
Maximum Data Rate 500 kbps
Propagation Delay, Low to High tDPLH 250 503 700 ns RL = 54 Ω, CL1 = C L2 = 100 pF, see Figure 25 and Figure 29
Propagation Delay, High to Low tDPHL 250 510 700 ns RL = 54 Ω, CL1 = C L2 = 100 pF, see Figure 25 and Figure 29
Output Skew tSKEW 7 100 ns RL = 54 Ω, CL1 = CL2 = 100 pF, see Figure 25 and Figure 29
Rise Time/Fall Time tDR, tDF 200 1100 ns RL = 54 Ω, CL1 = CL2 = 100 pF, see Figure 25 and Figure 29
Enable Time
t
ZL
, t
ZH
2.5
µs
R
L
= 110 , C
L
= 50 pF, see Figure 26 and Figure 31
Disable Time tLZ, tHZ 200 ns RL = 110 , CL = 50 pF, see Figure 26 and Figure 31
RECEIVER
Propagation Delay, Low to High
t
RPLH
91
200
ns
C
L
= 15 pF, see Figure 27 and Figure 30
Propagation Delay, High to Low tRPHL 95 200 ns CL = 15 pF, see Figure 27 and Figure 30
Output Skew tSKEW 4 30 ns CL = 15 pF, see Figure 27 and Figure 30
Enable Time tZL, tZH 15 ns RL = 1 k, CL = 15 pF, see Figure 28 and Figure 32
Disable Time tLZ, tHZ 15 ns RL = 1 k, CL = 15 pF, see Figure 28 and Figure 32
ADM2582E/ADM2587E PACKAGE CHARACTERISTICS
Table 4.
Parameter Symbol Min Typ Max Unit Test Conditions
Resistance (Input-to-Output)1 RI-O 1012
Capacitance (Input-to-Output)1 CI-O 3 pF f = 1 MHz
Input Capacitance2 CI 4 pF
1 Device considered a 2-terminal device: short together Pin 1 to Pin 10 and short together Pin 11 to Pin 20.
2 Input capacitance is from any input data pin to ground.
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 6 of 22
ADM2582E/ADM2587E REGULATORY INFORMATION
Table 5. ADM2582E/ADM2587E Approvals
Organization Approval Type Notes
UL
Recognized under the Component
Recognition Program of Underwriters
Laboratories, Inc.
In accordance with UL 1577, each ADM2582E/ADM2587E is proof tested
by applying an insulation test voltage ≥ 3000 V rms for 1 second.
VDE
Certified according to DIN EN 60747-5-2
(VDE 0884 Part 2): 2003-01
In accordance with DIN EN 60747-5-2, each ADM2582E/ADM2587E is
proof tested by applying an insulation test voltage ≥ 1050 VPEAK for
1 second.
ADM2582E/ADM2587E INSULATION AND SAFETY-RELATED SPECIFICATIONS
Table 6.
Parameter Symbol Value Unit Conditions
Rated Dielectric Insulation Voltage 2500 V rms 1-minute duration
Minimum External Air Gap (Clearance) L(I01) 7.7 mm Measured from input terminals to output terminals,
shortest distance through air
Minimum External Tracking (Creepage) L(I02) 7.6 mm Measured from input terminals to output terminals,
shortest distance along body
Minimum Internal Gap (Internal Clearance)
0.017 min
mm
Insulation distance through insulation
Tracking Resistance (Comparative Tracking Index) CTI >175 V DIN IEC 112/VDE 0303-1
Isolation Group IIIa Material Group (DIN VDE 0110: 1989-01, Table 1)
ADM2582E/ADM2587E VDE 0884 INSULATION CHARACTERISTICS
This isolator is suitable for basic electrical isolation only within the safety limit data. Maintenance of the safety data must be ensured by
means of protective circuits.
An asterisk (*) on packages denotes VDE 0884 Part 2 approval.
Table 7.
Description Conditions Symbol Characteristic Unit
CLASSIFICATIONS
Installation Classification per DIN VDE 0110 for
Rated Mains Voltage
≤150 V rms I to IV
≤300 V rms I to III
≤400 V rms
I to II
Climatic Classification 40/85/21
Pollution Degree DIN VDE 0110, see Table 1 2
VOLTAGE
Maximum Working Insulation Voltage VIORM 560 V peak
Input-to-Output Test Voltage VPR
Method b1 VIORM × 1.875 = VPR, 100% production tested,
tm = 1 sec, partial discharge < 5 pC
1050 V peak
Method a
After Environmental Tests, Subgroup 1 VIORM × 1.6 = VPR, tm = 60 sec, partial discharge < 5 pC 896 V peak
After Input and/or Safety Test,
Subgroup 2/Subgroup 3
VIORM × 1.2 = VPR, tm = 60 sec, partial discharge < 5 pC 672 V peak
Highest Allowable Overvoltage Transient overvoltage, tTR = 10 sec VTR 4000 V peak
SAFETY-LIMITING VALUES Maximum value allowed in the event of a failure
Case Temperature TS 150 °C
Input Current IS, INPUT 265 mA
Output Current
I
S
,
OUTPUT
335
mA
Insulation Resistance at TS VIO = 500 V RS >109
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 7 of 22
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted. All voltages are relative to
their respective ground.
Table 8.
Parameter Rating
VCC 0.5 V to +7 V
Digital Input Voltage (DE, RE, TxD) 0.5 V to VDD + 0.5 V
Digital Output Voltage (RxD) −0.5 V to VDD + 0.5 V
Driver Output/Receiver Input Voltage 9 V to +14 V
Operating Temperature Range 40°C to +85°C
Storage Temperature Range 55°C to +150°C
ESD (Human Body Model) on
A, B, Y, and Z pins
±15 kV
ESD (Human Body Model) on Other Pins ±2 kV
Thermal Resistance θJA 50°C/W
Lead Temperature
Soldering (10 sec) 260°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Table 9. Maximum Continuous Working Voltage1
Parameter Max Unit Reference Standard
AC Voltage
Bipolar Waveform
424
V peak
50-year minimum
lifetime
Unipolar Waveform
Basic Insulation 560 V peak Maximum approved
working voltage per
VDE 0884 Part 2
DC Voltage
Basic Insulation
560
V peak
Maximum approved
working voltage per
VDE 0884 Part 2
1 Refers to continuous voltage magnitude imposed across the isolation
barrier. See the Insulation Lifetime section for more details.
ESD CAUTION
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 8 of 22
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND
11
V
CC 2
GND
13
RxD
4
GND
2
20
V
ISOIN
19
A
18
B
17
RE
5
GND
2
16
DE
6
Z
15
TxD
7
GND
2
14
V
CC 8
Y
13
GND
19
V
ISOOUT
12
GND
110
GND
2
11
NOTES
1. PIN 12 AND PIN 19 MUST BE
CONNECTED E X TERNAL LY.
ADM2582E
ADM2587E
TOP VIEW
(No t t o Scal e)
08111-002
Figure 2. Pin Configuration
Table 10. Pin Function Description
Pin No. Mnemonic Description
1 GND1 Ground, Logic Side.
2 VCC Logic Side Power Supply. It is recommended that a 0.1 µF and a 0.01 µF decoupling capacitor be fitted between
Pin 2 and Pin 1. See Figure 35 for layout recommendations.
3 GND1 Ground, Logic Side.
4
RxD
Receiver Output Data. This output is high when (A B) −30 mV and low when (A B) ≤ –200 mV.
The output is tristated when the receiver is disabled, that is, when RE is driven high.
5 RE Receiver Enable Input. This is an active-low input. Driving this input low enables the receiver; driving it
high disables the receiver.
6 DE Driver Enable Input. Driving this input high enables the driver; driving it low disables the driver.
7 TxD Driver Input. Data to be transmitted by the driver is applied to this input.
8 VCC Logic Side Power Supply. It is recommended that a 0.1 µF and a 10 µF decoupling capacitor be fitted between
Pin 8 and Pin 9. See Figure 35 for layout recommendations.
9 GND1 Ground, Logic Side.
10 GND1 Ground, Logic Side.
11, 14 GND2 Ground for Isolated DC-to-DC Converter. It is recommended to connect Pin 11 and Pin 14 together through one
ferrite bead to PCB ground. See Figure 35 for layout recommendations.
12 VISOOUT Isolated Power Supply Output. This pin must be connected externally to VISOIN. It is recommended that a reservoir
capacitor of 10 µF and a decoupling capacitor of 0.1 µF be fitted between Pin 12 and Pin 11.
13 Y Driver Noninverting Output
15 Z Driver Inverting Output
16 GND2 Ground, Bus Side. Do not connect this pin to Pin 14 and Pin 11. See Figure 35 for layout recommendations.
17
B
Receiver Inverting Input.
18 A Receiver Noninverting Input.
19 VISOIN Isolated Power Supply Input. This pin must be connected externally to VISOOUT. It is recommended that a
0.1 µF and a 0.01 µF decoupling capacitor be fitted between Pin 19 and Pin 20. Connect this pin through a ferrite
bead and short trace length to VISOOUT for operation. See Figure 35 for layout recommendations.
20 GND2 Ground, Bus Side.
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 9 of 22
TYPICAL PERFORMANCE CHARACTERISTICS
20
0
40
60
80
100
120
140
160
180
–40 –15 10 35 60 85
SUPPLY CURRENT, I
CC
(mA)
TEMPERAT URE ( °C)
NO LOAD
R
L
= 120Ω
R
L
= 54Ω
08111-103
Figure 3. ADM2582E Supply Current (ICC) vs. Temperature
(Data Rate = 16 Mbps, DE = 3.3 V, VCC = 3.3 V)
20
0
40
60
80
100
120
140
–40 –15 10 35 60 85
SUPPLY CURRENT, I
CC
(mA)
TEMPERAT URE ( °C)
R
L
= 120Ω
R
L
= 54Ω
08111-104
NO LOAD
Figure 4. ADM2582E Supply Current (ICC) vs. Temperature
(Data Rate = 16 Mbps, DE = 5 V, VCC = 5 V)
20
0
40
60
80
100
120
–40 –15 10 35 60 85
SUPPLY CURRENT, ICC (mA)
TEMPERAT URE ( °C)
RL = 120Ω
RL = 54Ω
08111-106
NO LOAD
Figure 5. ADM2587E Supply Current (ICC) vs. Temperature
(Data Rate = 500 kbps, DE = 5 V, VCC = 5 V)
20
0
40
60
80
100
120
140
–40 –15 10 35 60 85
SUPPLY CURRENT, I
CC
(mA)
TEMPERAT URE ( °C)
R
L
= 120Ω
R
L
= 54Ω
08111-105
NO LOAD
Figure 6. ADM2587E Supply Current (ICC) vs. Temperature
(Data Rate = 500 kbps, DE = 3.3 V, VCC = 3.3 V)
50
52
54
56
58
60
62
64
66
68
70
72
DRIVE R P ROPAGATIO N DE LAY (ns)
TEMPERATURE (°C)
tDPHL
tDPLH
–40 –15 10 35 60 85
08111-107
Figure 7. ADM2582E Differential Driver Propagation Delay vs. Temperature
400
420
440
460
480
500
520
540
560
580
600
DRIVE R P ROPAGATIO N DE LAY ( ns)
TEMPERATURE (°C)
tDPHL
tDPLH
–40 –15 10 35 60 85
08111-108
Figure 8. ADM2587E Differential Driver Propagation Delay vs. Temperature
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 10 of 22
CH1 2.0V
CH3 2.0V CH2 2.0V
TxD
Y
Z
M10.00ns A CH1 1. 28V
1
3
08111-109
Figure 9. ADM2582E Driver Propagation Delay
CH1 2.0V
CH3 2.0V CH2 2.0V M200ns A CH1 2.56V
1
3
08111-110
TxD
Y
Z
Figure 10. ADM2587E Driver Propagation Delay
–70
–60
–50
–40
–30
–20
–10
0
012345
OUT P UT CURRENT (mA)
OUTPUT VOLTAGE (V)
08111-111
Figure 11. Receiver Output Current vs. Receiver Output High Voltage
0
10
20
30
40
50
60
01 2 3 4 5
OUT P UT CURRENT (mA)
OUTPUT VOLTAGE (V)
08111-112
Figure 12. Receiver Output Current vs. Receiver Output Low Voltage
4.65
4.66
4.67
4.68
4.69
4.70
4.71
4.72
4.73
4.74
4.75
OUTPUT VOLTAGE(V)
TEMPERATURE (°C)
–40 –15 10 35 60 85
08111-113
Figure 13. Receiver Output High Voltage vs. Temperature
0.20
0.22
0.24
0.26
0.28
0.30
0.32
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
–40 –15 10 35 60 85
08111-114
Figure 14. Receiver Output Low Voltage vs. Temperature
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 11 of 22
B
A
RxD
CH1 2.0V
CH3 2.0V CH2 2.0V M10.00ns A CH1 2.56V
1
3
08111-115
Figure 15. ADM2582E Receiver Propagation Delay
CH1 2.0V
CH3 2.0V CH2 2.0V M10.00ns A CH1 2. 56V
1
3
08111-116
B
A
RxD
Figure 16. ADM2587E Receiver Propagation Delay
93
92
94
95
96
97
98
–40 –15 10 35 60 85
RECEIVER PROPAGATION DELAY (ns)
TEMPERAT URE ( °C)
tRPHL
tRPLH
08111-117
Figure 17. ADM2582E Receiver Propagation Delay vs. Temperature
90
91
92
93
94
95
96
97
98
99
100
RECEI V E R P ROPAGATIO N DE LAY (ns)
TEMPERATURE (°C)
tRPHL
tRPLH
–40 –15 10 35 60 85
08111-118
Figure 18. ADM2587E Receiver Propagation Delay vs. Temperature
3.26
3.27
3.28
3.29
3.30
3.31
3.32
3.33
ISOLAT ED SUPPLY VOL T AGE (V)
NO LOAD
R
L
= 120Ω
R
L
= 54Ω
–40 –15 10 35 60 85
TEMPERAT URE ( °C)
08111-119
Figure 19. ADM2582E Isolated Supply Voltage vs. Temperature
(VCC = 3.3 V, Data Rate = 16 Mbps)
3.26
3.27
3.28
3.29
3.31
3.33
3.35
3.30
3.32
3.34
3.36
ISOLAT ED SUPPLY VOL T AGE (V)
NO LOAD
R
L
= 120Ω
R
L
= 54Ω
–40 –15 10 35 60 85
TEMPERAT URE ( °C)
08111-120
Figure 20. ADM2582E Isolated Supply Voltage vs. Temperature
(VCC = 5 V, Data Rate = 16 Mbps)
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 12 of 22
10
0
20
30
40
50
60
–40 –15 10 35 60 85
ISOLATED SUPPLY CURRENT (mA)
TEMPERAT URE ( °C)
NO LOAD
R
L
= 120Ω
R
L
= 54Ω
08111-121
Figure 21. ADM2582E Isolated Supply Current vs. Temperature
(VCC = 3.3 V, Data Rate = 16 Mbps)
5
0
10
15
25
20
30
35
40
–40 –15 10 35 60 85
ISOLATED SUPPLY CURRENT (mA)
TEMPERAT URE ( °C)
NO LOAD
RL = 120Ω
RL = 54Ω
08111-122
Figure 22. ADM2587E Isolated Supply Current vs. Temperature
(VCC = 3.3 V, Data Rate = 500 kbps)
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 13 of 22
TEST CIRCUITS
Y
Z
TxD V
OD2
V
OC
R
L
R
L
2
2
08111-003
Figure 23. Driver Voltage Measurement
Y
Z
TxD VOD3
VTEST
375Ω
60Ω
375Ω
08111-004
Figure 24. Driver Voltage Measurement
Y
Z
TxD
C
L
C
L
R
L
08111-005
Figure 25. Driver Propagation Delay
Y
Z
TxD
DE
S1 S2
VCC
RL
110Ω
VOUT
CL
50pF
08111-006
Figure 26. Driver Enable/Disable
CL
VOUT
RE
A
B
08111-007
Figure 27. Receiver Propagation Delay
C
L
R
L
V
OUT
V
CC
RE
S1
S2
+1.5V
–1.5V
RE IN
08111-008
Figure 28. Receiver Enable/Disable
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 14 of 22
SWITCHING CHARACTERISTICS
Z
Y
t
DPLH
t
DR
t
DPHL
t
DF
1/2V
O
V
O
90% POINT
10% POINT
90% POINT
10% POINT
V
DIFF
= V
(Y)
– V
(Z)
–V
O
V
DIFF
t
SKEW
= │t
DPHL
t
DPLH
+V
O
0V
V
CC
V
CC
/2 V
CC
/2
08111-009
Figure 29. Driver Propagation Delay, Rise/Fall Timing
A – B
RxD
0V
1.5V 1.5V
V
OL
V
OH
t
RPLH
0V
t
RPHL
t
SKEW = |
t
RPLH
t
RPHL
|
08111-010
Figure 30. Receiver Propagation Delay
DE
Y, Z
Y, Z
V
CC
0V
V
OL
V
OH
0.5V
CC
0.5V
CC
t
ZL
t
ZH
t
LZ
t
HZ
V
OH
– 0.5V
V
OL
+ 0.5V
2.3V
2.3V
08111-011
Figure 31. Driver Enable/Disable Timing
OUTPUT LOW
OUTPUT HIGH
1.5V
1.5V
RO
RO
RE
0V
0.5VCC 0.5VCC
0.7V
CC
0.3V
CC
t
ZL
t
ZH
t
LZ
t
HZ
V
OH
– 0.5V
V
OL
+ 0.5V V
OL
V
OH
08111-012
Figure 32. Receiver Enable/Disable Timing
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 15 of 22
CIRCUIT DESCRIPTION
SIGNAL ISOLATION
The ADM2582E/ADM2587E signal isolation is implemented on
the logic side of the interface. The part achieves signal isolation
by having a digital isolation section and a transceiver section
(see Figure 1). Data applied to the TxD and DE pins and referenced
to logic ground (GND1) are coupled across an isolation barrier
to appear at the transceiver section referenced to isolated ground
(GND2). Similarly, the single-ended receiver output signal,
referenced to isolated ground in the transceiver section, is
coupled across the isolation barrier to appear at the RXD pin
referenced to logic ground.
POWER ISOLATION
The ADM2582E/ADM2587E power isolation is implemented
using an isoPower integrated isolated dc-to-dc converter. The
dc-to-dc converter section of the ADM2582E/ADM2587E works
on principles that are common to most modern power supplies. It
is a secondary side controller architecture with isolated pulse-width
modulation (PWM) feedback. VCC power is supplied to an
oscillating circuit that switches current into a chip-scale air core
transformer. Power transferred to the secondary side is rectified
and regulated to 3.3 V. The secondary (VISO) side controller
regulates the output by creating a PWM control signal that is
sent to the primary (VCC) side by a dedicated iCoupler data
channel. The PWM modulates the oscillator circuit to control
the power being sent to the secondary side. Feedback allows for
significantly higher power and efficiency.
TRUTH TABLES
The truth tables in this section use the abbreviations found in
Table 11.
Table 11. Truth Table Abbreviations
Letter Description
H High level
L Low level
X Don’t care
Z High impedance (off)
NC
Disconnected
Table 12. Transmitting (see Table 11 for Abbreviations)
Inputs Outputs
DE TxD Y Z
H H H L
H L L H
L X Z Z
Table 13. Receiving (see Table 11 for Abbreviations)
Inputs Output
A − B RE RxD
−0.03 V L or NC H
−0.2 V L or NC L
−0.2 V < A − B < −0.03 V
L or NC
X
Inputs open L or NC
H
X H
Z
THERMAL SHUTDOWN
The ADM2582E/ADM2587E contain thermal shutdown circuitry
that protects the parts from excessive power dissipation during
fault conditions. Shorting the driver outputs to a low impedance
source can result in high driver currents. The thermal sensing
circuitry detects the increase in die temperature under this
condition and disables the driver outputs. This circuitry is
designed to disable the driver outputs when a die temperature
of 150°C is reached. As the device cools, the drivers are reenabled
at a temperature of 140°C.
OPEN- AND SHORT-CIRCUIT, FAIL-SAFE RECEIVER
INPUTS
The receiver inputs have open- and short-circuit, fail-safe
features that ensure that the receiver output is high when the
inputs are open or shorted. During line-idle conditions, when no
driver on the bus is enabled, the voltage across a terminating
resistance at the receiver input decays to 0 V. With traditional
transceivers, receiver input thresholds specified between −200 mV
and +200 mV mean that external bias resistors are required on the
A and B pins to ensure that the receiver outputs are in a known
state. The short-circuit, fail-safe receiver input feature eliminates
the need for bias resistors by specifying the receiver input threshold
between −30 mV and −200 mV. The guaranteed negative threshold
means that when the voltage between A and B decays to 0 V, t h e
receiver output is guaranteed to be high.
DC CORRECTNESS AND MAGNETIC FIELD IMMUNITY
The digital signals transmit across the isolation barrier using
iCoupler technology. This technique uses chip-scale transformer
windings to couple the digital signals magnetically from one
side of the barrier to the other. Digital inputs are encoded into
waveforms that are capable of exciting the primary transformer
winding. At the secondary winding, the induced waveforms are
decoded into the binary value that was originally transmitted.
Positive and negative logic transitions at the isolator input cause
narrow (~1 ns) pulses to be sent to the decoder via the transformer.
The decoder is bistable and is, therefore, either set or reset by the
pulses, indicating input logic transitions. In the absence of logic
transitions at the input for more than 1 µs, periodic sets of refresh
pulses indicative of the correct input state are sent to ensure dc
correctness at the output. If the decoder receives no internal pulses
of more than approximately 5 µs, the input side is assumed to be
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 16 of 22
unpowered or nonfunctional, in which case, the isolator output
is forced to a default state by the watchdog timer circuit.
This situation should occur in the ADM2582E/ADM2587E
devices only during power-up and power-down operations. The
limitation on the ADM2582E/ADM2587E magnetic field
immunity is set by the condition in which induced voltage in
the transformer receiving coil is sufficiently large to either
falsely set or reset the decoder. The following analysis defines
the conditions under which this can occur.
The 3.3 V operating condition of the ADM2582E/ADM2587E
is examined because it represents the most susceptible mode of
operation. The pulses at the transformer output have an amplitude
of >1.0 V. The decoder has a sensing threshold of about 0.5 V,
thus establishing a 0.5 V margin in which induced voltages can
be tolerated. The voltage induced across the receiving coil is
given by
V = (−/dt)Σπrn2; n = 1, 2, … , N
where:
β is magnetic flux density (gauss).
N is the number of turns in the receiving coil.
rn is the radius of the nth turn in the receiving coil (cm).
Given the geometry of the receiving coil in the ADM2582E/
ADM2587E and an imposed requirement that the induced
voltage be, at most, 50% of the 0.5 V margin at the decoder, a
maximum allowable magnetic field is calculated as shown in
Figure 33.
MAG NETI C FI ELD F RE QUENCY ( Hz )
100
MAXIMUM ALLOWABLE MAGNETIC FLUX
DENSI TY ( kGau ss)
0.001 1M
10
0.01
1k 10k 10M
0.1
1
100M
100k
08111-019
Figure 33. Maximum Allowable External Magnetic Flux Density
For example, at a magnetic field frequency of 1 MHz, the
maximum allowable magnetic field of 0.2 kgauss induces a
voltage of 0.25 V at the receiving coil. This is about 50% of the
sensing threshold and does not cause a faulty output transition.
Similarly, if such an event occurs during a transmitted pulse
(and is of the worst-case polarity), it reduces the received pulse
from >1.0 V to 0.75 V, which is still well above the 0.5 V sensing
threshold of the decoder.
The preceding magnetic flux density values correspond to
specific current magnitudes at given distances from the
ADM2582E/ADM2587E transformers. Figure 34 expresses
these allowable current magnitudes as a function of frequency
for selected distances. As shown in Figure 34, the ADM2582E/
ADM2587E are extremely immune and can be affected only by
extremely large currents operated at high frequency very close
to the component. For the 1 MHz example, a 0.5 kA current must
be placed 5 mm away from the ADM2582E/ADM2587E to affect
component operation.
MAG NETI C FI E LD FRE QUENCY ( Hz )
MAXI MUM AL LO WABLE CURRE NT (kA)
1k
100
10
1
0.1
0.011k 10k 100M100k 1M 10M
DISTANCE = 5mm
DISTANCE = 1m
DISTANCE = 100mm
08111-020
Figure 34. Maximum Allowable Current for Various
Current-to-ADM2582E/ADM2587E Spacings
Note that in combinations of strong magnetic field and high
frequency, any loops formed by printed circuit board (PCB)
traces can induce error voltages sufficiently large to trigger the
thresholds of succeeding circuitry. Take care in the layout of
such traces to avoid this possibility.
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 17 of 22
APPLICATIONS INFORMATION
PCB LAYOUT AND ELECTROMAGNETIC
INTERFERENCE (EMI)
The ADM2582E/ADM2587E isolated RS-422/RS-485 transceiver
contains an isoPower integrated dc-to-dc converter, requiring
no external interface circuitry for the logic interfaces. Power
supply bypassing is required at the input and output supply pins
(see Figure 35). The power supply section of the ADM2582E/
ADM2587E uses a 180 MHz oscillator frequency to pass power
efficiently through its chip-scale transformers. In addition, the
normal operation of the data section of the iCoupler introduces
switching transients on the power supply pins.
Bypass capacitors are required for several operating frequencies.
Noise suppression requires a low inductance, high frequency
capacitor, whereas ripple suppression and proper regulation
require a large value capacitor. These capacitors are connected
between Pin 1 (GND1) and Pin 2 (VCC) and Pin 8 (VCC) and
Pin 9 (GND1) for VCC. The VISOIN and VISOOUT capacitors are
connected between Pin 11 (GND2) and Pin 12 (VISOOUT) and
Pin 19 (VISOIN) and Pin 20 (GND2). To suppress noise and reduce
ripple, a parallel combination of at least two capacitors is required
with the smaller of the two capacitors located closest to the device.
The recommended capacitor values are 0.1 µF and 10 µF for
VISOOUT at Pin 11 and Pin 12 and VCC at Pin 8 and Pin 9. Capacitor
values of 0.01 µF and 0.1 µF are recommended for VISOIN at
Pin 19 and Pin 20 and VCC at Pin 1 and Pin 2. The recommended
best practice is to use a very low inductance ceramic capacitor,
or its equivalent, for the smaller value. The total lead length
between both ends of the capacitor and the input power supply
pin should not exceed 10 mm.
The dc-to-dc converter section of the ADM2582E/ADM2587E
components must operate, out of necessity, at a very high
frequency to allow efficient power transfer through the small
transformers. This creates high frequency currents that can
propagate in circuit board ground and power planes, causing edge
and dipole radiation.
The ADM2582E/ADM2587E features an internal split paddle,
lead frame on the bus side. For the best noise suppression, filter
both the GND2 pins (Pin 11 and Pin 14) and VISOOUT signals of
the integrated dc-to-dc converter for high frequency currents.
Use surface-mount ferrite beads in series with the signals before
routing back to the device. See Figure 35 for the recommended
PCB layout. The impedance of the ferrite bead is chosen to be
about 2 kΩ between the 100 MHz and 1 GHz frequency range
to reduce the emissions at the 180 MHz primary switching
frequency and the 360 MHz secondary side rectifying
frequency and harmonics.
To pass the EN55022 radiated emissions standard, the following
additional layout guidelines are recommended:
Do not connect the VISOOUT pin to a power plane;
connect between VISOOUT and VISOIN using a PCB trace.
Ensure that VISOIN (Pin 19) connects through the L1
ferrite to VISOOUT (Pin 12), as shown in Figure 35.
If using a four layer PCB, place an embedded stitching
capacitor between GND1 and GND2 using internal
layers of the PCB planes. An embedded PCB capacitor
is created when two metal planes in a PCB overlap
each other and are separated by dielectric material.
This capacitor provides a return path for high
frequency common-mode noise currents across the
isolation gap.
If using a two layer PCB, place a high voltage discrete
capacitor that connects between GND1 (Pin 10) and
GND2 (Pin 11). This capacitor provides a return path
for high frequency common-mode noise currents
across the isolation gap.
Ensure that GND2 (Pin 14) connects to GND2 (Pin 11)
on the inside (device side) of the C1 100 nF capacitor.
Ensure that the C1 capacitor connects between VISOOUT
(Pin 12) and GND2 (Pin 11) on the device side of the
L1 and L2 ferrites.
Ensure that GND2 (Pin 16) is connected to GND2
(Pin 11) on the outside (bus side) of the L2 ferrite, as
shown in Figure 35.
Ensure that there is a keep out area for the GND2
plane in the PCB layout around the L1 and L2 ferrites.
The keep out area means there must not be a GND2
fill on any layer below the L1 and L2 ferrites.
Locate the power delivery circuit in close proximity to
the ADM2582E/ADM2587E device, so that the VCC
trace is as short as possible.
See the AN-1349 Application Note, PCB Implementation Guidelines
to Minimize Radiated Emissions on the ADM2582E/ADM2587E RS-
485/RS-422 Transceivers, for more information. Evaluation boards
and user guides are available for two layer and four layer PCB
EN55022 radiated emissions compliant designs. See UG-916 and
UG-044 for more information.
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 18 of 22
R
D
TRANSCEIVER
DIGITAL
ISOLATION
isoPOWER
DC-TO-DC CONVERT ER
V
CC 2
GND
13
4
20
V
ISOIN
19
18
17
516
615
7
GND
2
GND
2
GND
2
14
V
CC 813
GND
19
V
ISOOUT
12
GND
110
10µF
10µF
10nF
C1
100nF
L1
L2
STIT CHING CAPACITOR ACROS S
ISOLATI O N BARRIE R REQ UIRED
FOR EN55022/CI S PR22 CL AS S B
FERRITE
BEADS
PCB KEE P O UT AREA
PCB T RACE
CONNECTING
PI N 11 AND PI N 14
100nF 100nF
11
GND
11
100nF
10nF
08111-035
Figure 35. Recommended PCB Layout
In applications involving high common-mode transients, ensure
that board coupling across the isolation barrier is minimized.
Furthermore, design the board layout such that any coupling
that does occur equally affects all pins on a given component
side. Failure to ensure this can cause voltage differentials between
pins exceeding the absolute maximum ratings for the device,
thereby leading to latch-up and/or permanent damage.
The ADM2582E/ADM2587E dissipate approximately 650 mW
of power when fully loaded. Because it is not possible to apply a
heat sink to an isolation device, the devices primarily depend
on heat dissipation into the PCB through the GND pins. If the
devices are used at high ambient temperatures, provide a thermal
path from the GND pins to the PCB ground plane. The board
layout in Figure 35 shows enlarged pads for Pin 1, Pin 3, Pin 9,
Pin 10, Pin 11, Pin 14, Pin 16, and Pin 20. Implement multiple
vias from the pad to the ground plane to reduce the temperature
inside the chip significantly. The dimensions of the expanded
pads are at the discretion of the designer and dependent on the
available board space.
INSULATION LIFETIME
All insulation structures eventually break down when subjected to
voltage stress over a sufficiently long period. The rate of insulation
degradation is dependent on the characteristics of the voltage
waveform applied across the insulation. Analog Devices conducts
an extensive set of evaluations to determine the lifetime of the
insulation structure within the ADM2582E/ADM2587E.
Accelerated life testing is performed using voltage levels higher
than the rated continuous working voltage. Acceleration factors for
several operating conditions are determined, allowing calculation
of the time to failure at the working voltage of interest. The values
shown in Table 9 summarize the peak voltages for 50 years of
service life in several operating conditions. In many cases, the
working voltage approved by agency testing is higher than the
50-year service life voltage. Operation at working voltages higher
than the service life voltage listed leads to premature insulation
failure.
The insulation lifetime of the ADM2582E/ADM2587E depends
on the voltage waveform type imposed across the isolation barrier.
The iCoupler insulation structure degrades at different rates,
depending on whether the waveform is bipolar ac, unipolar ac,
or dc. Figure 36, Figure 37, and Figure 38 illustrate these different
isolation voltage waveforms.
Bipolar ac voltage is the most stringent environment. A 50-year
operating lifetime under the bipolar ac condition determines
the Analog Devices recommended maximum working voltage.
In the case of unipolar ac or dc voltage, the stress on the insulation
is significantly lower. This allows operation at higher working
voltages while still achieving a 50-year service life. The working
voltages listed in Table 9 can be applied while maintaining the
50-year minimum lifetime, provided the voltage conforms to either
the unipolar ac or dc voltage cases. Any cross insulation voltage
waveform that does not conform to Figure 37 or Figure 38 should
be treated as a bipolar ac waveform, and its peak voltage should
be limited to the 50-year lifetime voltage value listed in Table 9.
0V
RATED P E AK V OLTAGE
08111-021
Figure 36. Bipolar AC Waveform
0V
RAT E D P EAK VOL TAGE
08111-023
Figure 37. DC Waveform
0V
RATED P EAK VOL T AGE
NOTES
1. THE V OL TAGE IS SHOW N AS SINUSO DIAL FO R IL LUSTRATIO N
PURPOSES ONLY. IT I S MEANT TO REPRESENT ANY VOLTAGE
WAV E FO RM VARYING BETWEEN 0 AND SOME LIMITI NG VALUE.
THE LI M IT ING V A L UE CAN BE P OSITIVE OR NEGAT IVE, BUT THE
VO LT AGE CANNOT CROSS 0 V .
08111-022
Figure 38. Unipolar AC Waveform
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 19 of 22
ISOLATED POWER SUPPLY CONSIDERATIONS
The typical output voltage of the integrated isoPower dc-to-dc
isolated supply is 3.3 V. The isolated supply in the ADM2587E is
capable of supplying a current of 55 mA when the junction
temperature of the device is kept below 120°C. It is important to
note that the current available on the VISOOUT pin is the total current
available and includes the current required to supply the
internal RS-485 circuitry.
The ADM2587E can typically supply 15 mA externally on
VISOOUT when the driver is switching at 500 kbps loaded with 54 Ω,
while the junction temperature of the part is less than 120°C.
Table 14. Typical Maximum External Current Available
on VISOOUT
External Load Current (mA) RT System Configuration
15 54 Double terminated
bus with RT = 110
29 120 Single terminated bus
46 Unloaded Unterminated bus
The ADM2582E typically has no current available externally
on VISOOUT.
When external current is drawn from the VISOOUT pin, there is
an increased risk of generating radiated emissions due to the
high frequency switching elements used in the isoPower dc to-dc
converter. Special care must be taken during PCB layout to
meet emissions standards. See Application Note AN-0971,
Control of Radiated Emissions with isoPower Devices, for details
on board layout considerations.
ADM2582E/ADM2587E
TxD
A
B
Y
Z
DE
V
CC
V
CC
V
CC
RxD
RE
ISOLATION
BARRIER
TRANSCEIVER
GND
1
GND
2
GND
2
GND
1
R
T
ENCODE
ENCODE
DECODE
DECODE D
R
DECODE
ENCODE
OSCILLATOR RECTIFIER
REGULATOR
EXTERNAL
LOAD
V
ISOOUT
DIGITAL ISOLATION iCoupler
isoPower DC-TO-DC CONVERTER
V
ISOIN
08111-038
500kbps
GND
Figure 39. ADM2587E Typical Maximum External Current Measurements
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 20 of 22
TYPICAL APPLICATIONS
An example application of the ADM2582E/ADM2587E for a full-
duplex RS-485 node is shown in the circuit diagram of Figure 40.
Refer to the PCB Layout and Electromagnetic Interference
(EMI) section for the recommended placement of the capacitors
shown in this circuit diagram. Placement of the RT termination
resistors depends on the location of the node and the network
configuration. Refer to the AN-960 Application Note,
RS-485/ RS-422 Circuit Implementation Guide, for guidance on
termination.
Figure 41 and Figure 42 show typical applications of the
ADM2582E/ADM2587E in half duplex and full duplex RS-485
network configurations. Up to 256 transceivers can be connected to
the RS-485 bus. To minimize reflections, terminate the line at the
receiving end in its characteristic impedance and keep stub lengths
off the main line as short as possible. For half-duplex operation, this
means that both ends of the line must be terminated because either
end can be the receiving end.
ADM2582E/ADM2587E
TxD
A
B
Y
Z
DE
RxD
RE
ISOLATION
BARRIER
TRANSCEIVER
GND1
GND1
GND2
ENCODE
ENCODE
ENCODE
DECODE
DECODE
DECODE D
R
OSCILLATOR RECTIFIER
REGULATOR
VISOOUT
VCC
VCC
VISOIN
MICROCONTROLLER
AND UART
R
T
3.3V/5V POWER
SUPPLY
100nF 10µF 100nF 10nF
100nF 10µF
100nF 10nF
DIGITAL ISOLATION iCoupler
isoPower DC-TO- DC CONVE RTER
08111-124
Figure 40. Example Circuit Diagram Using the ADM2582E/ADM2587E
Data Sheet ADM2582E/ADM2587E
Rev. G | Page 21 of 22
NOTES
1. RT IS EQ UAL TO THE CHARACTERIST IC I M P E DANCE OF THE CABLE.
2. ISOLATION NOT SHOWN.
A B Z YA B Z Y
A
B
Z
Y
A
B
Z
Y
RDRD
R
D
R
D
ADM2582E/
ADM2587E
ADM2582E/
ADM2587E
ADM2582E/
ADM2587E
RxD RE DE TxDRxD RE DE TxD
RTRT
RxD
RE
DE
TxD
RxD
RE
DE
TxD
ADM2582E/
ADM2587E
MAXIMUM NUMBE R OF TRANSCEIVERS ON BUS = 256
08111-027
Figure 41. ADM2582E/ADM2587E Typical Half-Duplex RS-485 Network
NOTES
1. RT IS EQ UAL TO THE CHARACTERIST IC I M P E DANCE OF THE CABLE.
2. ISOLATION NOT SHOWN.
R
D
A
B
Z
Y
RD
AB Z Y
R
D
A
B
Z
Y
RD
A B Z Y
RT
TxD
DE
RxD
RE
ADM2582E/
ADM2587E
ADM2582E/
ADM2587E
ADM2582E/
ADM2587E
SLAVE
RxD
RE
DE
TxD
ADM2582E/
ADM2587E
MASTER
SLAVE
SLAVE
RxD RE DE TxD
RxD RE DE TxD
RT
MAXIMUM NUMBE R OF NODES = 2 56
08111-028
Figure 42. ADM2582E/ADM2587E Typical Full Duplex RS-485 Network
ADM2582E/ADM2587E Data Sheet
Rev. G | Page 22 of 22
OUTLINE DIMENSIONS
CONTROLLING DIMENSIONSAREIN MILLIMETERS; INCHDIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
COMPLIANT TO JEDEC STANDARDSMS-013-AC
13.00(0.5118)
12.60 (0.4961)
0.30(0.0118)
0.10 (0.0039)
2.65(0.1043)
2.35 (0.0925)
10.65 (0.4193)
10.00(0.3937)
7.60 (0.2992)
7.40 (0.2913)
0.75(0.0295)
0.25(0.0098)
4
1.27 (0.0500)
0.40 (0.0157)
COPLANARITY
0.100.33 (0.0130)
0.20(0.0079)
0.51 (0.0201)
0.31 (0.0122)
SEATING
PLANE
0°
20 11
10
1
1.27
(0.0500)
BSC
06-07-2006-A
Figure 43. 20-Lead Standard Small Outline Package [SOIC_W]
Wide Body
(RW-20)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model1
Data Rate
(Mbps)
Temperature
Range Package Description
Package
Option
ADM2582EBRWZ 16 40°C to +85°C 20-Lead SOIC_W RW-20
ADM2582EBRWZ-REEL7 16 −40°C to +85°C 20-Lead SOIC_W RW-20
ADM2587EBRWZ 0.5 −40°C to +85°C 20-Lead SOIC_W RW-20
ADM2587EBRWZ-REEL7 0.5 −40°C to +85°C 20-Lead SOIC_W RW-20
EVAL-ADM2582EEBZ ADM2582E Evaluation Board
EVAL-ADM2582EEMIZ ADM2582E EMI Compliant Evaluation Board
EVAL-ADM2587EEBZ ADM2587E Evaluation Board
EVAL-ADM2587EEMIZ ADM2587E EMI Compliant Evaluation Board
EVAL-ADM2587EARDZ ADM2587E Arduino Evaluation Board
EVAL-ADM2587ERPIZ ADM2587E Raspberry Pi Evaluation Board
EVAL-ADM2587EEB2Z ADM2587E Isolated RS-485 Repeater Evaluation Board
1 Z = RoHS Compliant Part.
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