Full-Duplex, Low Power,
Slew Rate Limited, EIA RS-485 Transceivers
ADM488/ADM489
FEATURES
Meets EIA RS-485 and RS-422 standards
250 kbps data rate
Single 5 V ± 10% supply
−7 V to +12 V bus common-mode range
12 kΩ input impedance
2 kV EFT protection meets IEC1000-4-4
High EM immunity meets IEC1000-4-3
Reduced slew rate for low EM interference
Short-circuit protection
Excellent noise immunity
30 μA supply current
FUNCTIONAL BLOCK DIAGRAMS
ADM488
A
RO
R
B
Z
DI
D
00079-001
00079-002
Y
Figure 1.
ADM489
A
RO
RE
DE
Z
DI
D
Y
R
B
APPLICATIONS
Low power RS-485 and RS-422 systems
DTE-DCE interface
Packet switching
Local area networks
Data concentration
Data multiplexers
Integrated services digital network (ISDN)
Figure 2.
GENERAL DESCRIPTION
The ADM488 and ADM489 are low power, differential line
transceivers suitable for communication on multipoint bus
transmission lines. They are intended for balanced data
transmission and comply with both Electronics Industries
Association (EIA) RS-485 and RS-422 standards. Both products
contain a single differential line driver and a single differential
line receiver, making them suitable for full-duplex data transfer.
The ADM489 contains an additional receiver and driver enable
control.
The input impedance is 12 kΩ, allowing 32 transceivers to be
connected on the bus.
The ADM488/ADM489 operate from a single 5 V ± 10% power
supply. Excessive power dissipation caused by bus contention or
output shorting is prevented by a thermal shutdown circuit.
This feature forces the driver output into a high impedance state
if, during fault conditions, a significant temperature increase is
detected in the internal driver circuitry.
The receiver contains a fail-safe feature that results in a logic
high output state if the inputs are unconnected (floating).
The ADM488/ADM489 are fabricated on BiCMOS, an
advanced mixed technology process combining low power
CMOS with fast switching bipolar technology.
The ADM488/ADM489 are fully specified over the industrial
temperature range and are available in PDIP, SOIC, and TSSOP
packages.
Rev. D
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 that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2006 Analog Devices, Inc. All rights reserved.
ADM488/ADM489
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagrams............................................................. 1
Specifications..................................................................................... 3
Timing Specifications .................................................................. 4
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Test Circuits................................................................................... 7
Switching Characteristics ............................................................ 8
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 11
EFT Transient Protection Scheme ........................................... 11
Fast Transient Burst Immunity (IEC1000-4-4)...................... 11
Radiated Immunity (IEC1000-4-3) ......................................... 12
EMI Emissions............................................................................ 13
Conducted Emissions ................................................................ 13
Application Information................................................................ 14
Differential Data Transmission ................................................ 14
Cable and Data Rate................................................................... 14
Outline Dimensions ....................................................................... 15
Ordering Guide .......................................................................... 16
REVISION HISTORY
4/06—Rev.
C to Rev. D
Updated Outline Dimensions ....................................................... 15
Changes to Ordering Guide .......................................................... 16
11/04—Rev. B to Rev. C
Updated Format..................................................................Universal
Changes to Receiving Truth Table Inputs Data Section ............ 11
Renamed General Information to Theory of Operation........... 12
Updated Outline Dimensions ....................................................... 15
Changes to Ordering Guide .......................................................... 16
5/01—Rev. A to Rev. B
Changes to Absolute Maximum Ratings Section......................... 3
3/01—Rev. 0 to Rev. A
Changes to ESD Specification, Absolute Maximum Ratings...... 3
6/97—Revision 0: Initial Version
Rev. D | Page 2 of 16
ADM488/ADM489
SPECIFICATIONS
V
CC
= 5 V ± 10%. All specifications T
MIN
to T
MAX
, unless otherwise noted.
Table 1.
Parameter
DRIVER
Differential Output Voltage, V
OD
2.0
1.5
1.5
Δ|V
OD
| for Complementary Output States
Common-Mode Output Voltage, V
OC
Δ|V
OC
| for Complementary Output States
Output Short-Circuit Current (V
OUT
= High)
Output Short-Circuit Current (V
OUT
= Low)
CMOS Input Logic Threshold Low, V
INL
CMOS Input Logic Threshold High, V
INH
Logic Input Current (DE, DI)
RECEIVER
Differential Input Threshold Voltage, V
TH
Input Voltage Hysteresis, Δ V
TH
Input Resistance
Input Current (A, B)
Logic Enable Input Current (RE)
CMOS Output Voltage Low, V
OL
CMOS Output Voltage High, V
OH
Short-Circuit Output Current
Three-State Output Leakage Current
POWER SUPPLY CURRENT
I
CC
Min
Typ
Max
5.0
5.0
5.0
5.0
0.2
3
0.2
250
250
0.8
±1.0
−0.2
70
12
1
−0.8
±1
0.4
4.0
7
85
±1.0
30
37
60
74
+0.2
Unit
V
V
V
V
V
V
V
mA
mA
V
V
μA
V
mV
kΩ
mA
mA
μA
V
V
mA
μA
μA
μA
Test Conditions/Comments
R = ∞, see Figure 6
V
CC
= 5 V, R = 50 Ω (RS-422), see Figure 6
R = 27 Ω (RS-485), see Figure 6
V
TST
= –7 V to +12 V, see Figure 7, V
CC
= 5 V ± 5%
R = 27 Ω or 50 Ω, see Figure 6
R = 27 Ω or 50 Ω, see Figure 6
R = 27 Ω or 50 Ω
−7 V ≤ V
O
≤ +12 V
−7 V ≤ V
O
≤ +12 V
2.0
1.4
1.4
−7 V ≤ V
CM
≤ +12 V
V
CM
= 0 V
−7 V ≤ V
CM
≤ +12 V
V
IN
= 12 V
V
IN
= –7 V
I
OUT
= +4.0 mA
I
OUT
= −4.0 mA
V
OUT
= GND or V
CC
0.4 V ≤ V
OUT
≤ +2.4 V
Outputs unloaded, receivers enabled
DE = 0 V (disabled)
DE = 5 V (enabled)
Rev. D | Page 3 of 16
ADM488/ADM489
TIMING SPECIFICATIONS
V
CC
= 5 V ± 10%. All specifications T
MIN
to T
MAX
, unless otherwise noted.
Table 2.
Parameter
DRIVER
Propagation Delay Input to Output, T
PLH
, T
PHL
Driver O/P to OP, T
SKEW
Driver Rise/Fall Time, T
R
, T
F
Driver Enable to Output Valid
Driver Disable Timing
Data Rate
RECEIVER
Propagation Delay Input to Output, T
PLH
, T
PHL
Skew |T
PLH
− T
PHL
|
Receiver Enable, T
EN1
Receiver Disable, T
EN2
Data Rate
250
250
300
250
250
100
10
10
250
Min
250
100
Typ
Max
2000
800
2000
2000
3000
Unit
ns
ns
ns
ns
ns
kbps
ns
ns
ns
ns
kbps
Test Conditions/Comments
R
L
Differential = 54 Ω, C
L1
= C
L2
= 100 pF,
see Figure 10
R
L
Differential = 54 Ω, C
L1
= C
L2
= 100 pF,
see Figure 10
R
L
Differential = 54 Ω, C
L1
= C
L2
= 100 pF,
see Figure 10
R
L
= 500 Ω, C
L
= 100 pF, see Figure 7
R
L
= 500 Ω, C
L
= 15 pF, see Figure 7
2000
50
50
C
L
= 15 pF, see Figure 10
R
L
= 1 kΩ, C
L
= 15 pF, see Figure 9
R
L
= 1 kΩ, C
L
= 15 pF, see Figure 9
Rev. D | Page 4 of 16
ADM488/ADM489
ABSOLUTE MAXIMUM RATINGS
T
A
= 25°C, unless otherwise noted.
Table 3.
Parameter
V
CC
Inputs
Driver Input (DI)
Control Inputs (DE, RE)
Receiver Inputs (A, B)
Outputs
Driver Outputs
Receiver Output
Power Dissipation 8-Lead PDIP
θ
JA
, Thermal Impedance
Power Dissipation 8-Lead SOIC
θ
JA
, Thermal Impedance
Power Dissipation 14-Lead PDIP
θ
JA
, Thermal Impedance
Power Dissipation 14-Lead SOIC
θ
JA
, Thermal Impedance
Power Dissipation 16-Lead TSSOP
θ
JA
, Thermal Impedance
Operating Temperature Range
Industrial (A Version)
Storage Temperature Range
Lead Temperature (Soldering, 10 sec)
Vapor Phase (60 sec)
Infrared (15 sec)
ESD Association S5.1 HBM Standard
EFT Rating, IEC1000-4-4
Rating
7V
−0.3 V to V
CC
+ 0.3 V
−0.3 V to V
CC
+ 0.3 V
−14 V to +14 V
−14 V to +12.5 V
−0.5 V to V
CC
+ 0.5 V
700 mW
120°C/W
520 mW
110°C/W
800 mW
140°C/W
800 mW
120°C/W
800 mW
150°C/W
−40°C to +85°C
−65°C to +150°C
300°C
215°C
220°C
3 kV
2 kV
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD 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. Although this product 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.
Rev. D | Page 5 of 16
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