Page 1
5 V Low Power, Slew-Rate Limited
FEATURES
EIA RS-485/RS-422-compliant
Data rates up to 250 kbps
Slew-rate limited for low EMI
100 nA supply current in shutdown mode
Low power consumption (120 µA)
Up to 32 transceivers on one bus
Outputs high-z when disabled or powered off
–7 V to +12 V bus common-mode range
Thermal shutdown and short-circuit protection
Pin-compatible with MAX483
Specified over –40°C to +85°C temperature range
Available in 8-lead SOIC package
APPLICATIONS
Low power RS-485 applications
EMI sensitive systems
DTE-DCE interfaces
Industrial control
Packet switching
Local area networks
Level translators
RS-485/RS-422 Transceiver
ADM483
FUNCTIONAL BLOCK DIAGRAM
V
CC
ADM483
RO
RE
DE
DI
R
D
GND
Figure 1.
A
B
05079-001
GENERAL DESCRIPTION
The ADM483 is a low power differential line transceiver suitable
for half-duplex data communication on multipoint bus transmission lines. It is designed for balanced data transmission, and
complies with EIA Standards RS-485 and RS-422.The part
contains a differential line driver and a differential line receiver.
Both share the same differential pins, with either the driver or
the receiver being enabled at any given time.
The device has an input impedance of 12 kΩ, allowing up to
32 transceivers on one bus. Since only one driver should be
enabled at any time, the output of a disabled or powered-down
driver is three-stated to avoid overloading the bus. This high
impedance driver output is maintained over the entire
common-mode voltage range from –7 V to +12 V.
Rev. 0
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.
The receiver contains a fail-safe feature that results in a logic
high output state if the inputs are unconnected (floating).
The driver outputs are slew-rate limited to reduce EMI and data
errors caused by reflections from improperly terminated buses.
Excessive power dissipation caused by bus contention or by
output shorting is prevented by a thermal shutdown circuit.
The part is fully specified over the industrial temperature range,
and is available in an 8-lead SOIC package.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.326.8703 © 2004 Analog Devices, Inc. All rights reserved.
www.analog.com
Page 2
ADM483
TABLE OF CONTENTS
Specifications..................................................................................... 3
Timing Specifications....................................................................... 4
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Test C ir c uit s ....................................................................................... 7
Switching Characteristics ................................................................ 8
Typical Performance Characteristics............................................. 9
REVISION HISTORY
10/04—Revision 0: Initial Version
Applications..................................................................................... 11
Differential Data Transmission ................................................ 11
Cable and Data Rate................................................................... 11
Thermal Shutdown .................................................................... 12
Receiver Open-Circuit Fail-Safe............................................... 12
Outline Dimensions ....................................................................... 13
Ordering Guide .......................................................................... 13
Rev. 0 | Page 2 of 16
Page 3
ADM483
SPECIFICATIONS
VCC = 5 V ± 5%, TA = T
Table 1.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Output Voltage, V
2.0 V R = 50 Ω (RS-422), Figure 3
1.5 5 V R = 27 Ω (RS-485), Figure 3
1.5 5 V V
∆ |VOD| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, Figure 3
Common-Mode Output Voltage, V
∆ |VOC| for Complementary Output States 0.2 V R = 27 Ω or 50 Ω, Figure 3
Output Short-Circuit Current, V
Output Short-Circuit Current, V
DRIVER INPUT LOGIC
CMOS Input Logic Threshold Low 0.8 V
CMOS Input Logic Threshold High 2.0 V
CMOS Logic Input Current (DI) ±2 µA
DE Input Resistance to GND
RECEIVER
Differential Input Threshold Voltage, V
Input Hysteresis 70 mV VCM = 0V
Input Resistance (A, B) 12 kΩ –7 V < VCM < +12 V
Input Current (A, B)
CMOS Logic Input Current (RE)
CMOS Output Voltage Low 0.4 V I
CMOS Output Voltage High 3.5 V I
Output Short-Circuit Current 7 95 mA 0 V < V
Three-State Output Leakage Current ±2 µA 0.4 ≤ V
POWER SUPPLY CURRENT 0.1 10 µA
120 250 µA
350 650 µA DE = VCC
MIN
to T
, unless otherwise noted.
MAX
OD
OC
= High 35 250 mA –7 V < V
OUT
= Low 35 250 mA –7 V < V
OUT
5 V
3 V R = 27 Ω or 50 Ω, Figure 3
220 kΩ
R = ∞, Figure 3
= –7 V to 12 V, Figure 4
TST
< +12 V
OUT
< +12 V
OUT
TH
–200 +200 mV –7 V < VCM < +12 V
1 mA VIN = +12 V
–0.8 mA VIN = –7 V
±2 µA
= 4 mA
OUT
= –4 mA
OUT
< V
OUT
≤ 2.4 V
OUT
DE = 0 V,
DE = 0 V,
RE = VCC (shutdown)
RE = 0 V
CC
Rev. 0 | Page 3 of 16
Page 4
ADM483
TIMING SPECIFICATIONS
VCC = 5 V ± 5%, TA = T
Table 2.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Maximum Data Rate 250 kbps
Propagation Delay t
Skew t
SKEW
Rise/Fall Time tR, tF 200 2000 ns R
Enable Time 125 2000 ns RL = 500 Ω, CL = 100 pF, Figure 6
Disable Time 125 3000 ns RL = 500 Ω, CL = 15 pF, Figure 6
Enable Time from Shutdown 5000 ns RL = 500 Ω, CL = 100 pF, Figure 6
RECEIVER
Propagation Delay t
Differential Skew t
Enable Time 20 50 ns RL = 1 kΩ, CL = 15 pF, Figure 8
Disable Time 20 50 ns RL = 1 kΩ, CL = 15 pF, Figure 8
Enable Time from Shutdown 5000 ns RL = 1 kΩ, CL = 15 pF, Figure 8
Time to Shutdown
1
The device is put into shutdown mode by driving RE high and DE low. If these inputs are in this state for less than 50 ns, the device is guaranteed not to enter
shutdown mode. If the enable inputs are in this state for at least 3000 ns, the device is guaranteed to have entered shutdown mode.
SKEW
1
PLH
PLH
MIN
to T
, t
, t
, unless otherwise noted.
MAX
250 800 2000 ns R
PHL
100 800 ns R
250 2000 ns CL = 15 pF, Figure 7
PHL
LDIFF
LDIFF
LDIFF
100 ns CL = 15 pF, Figure 7
50 330 3000 ns
= 54 Ω, CL1 = CL2 = 100 pF, Figure 5
= 54 Ω, CL1 = CL2 = 100 pF, Figure 5
= 54 Ω, CL1 = CL2 = 100 pF, Figure 5
Rev. 0 | Page 4 of 16
Page 5
ADM483
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 3.
Parameter Rating
VCC to GND 6 V
Digital I/O Voltage (DE, RE, DI, ROUT)
Driver Output/Receiver Input Voltage –9 V to +14 V
Operating Temperature Range –40°C to +85°C
Storage Temperature Range –65°C to +125°C
θJA Thermal Impedance (SOIC) 110°C/W
Lead Temperature
Soldering (10 s) 300°C
Vapor Phase (60 s) 215°C
Infrared (15 s) 220°C
–0.3 V to V
+ 0.3 V
CC
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. 0 | Page 5 of 16
Page 6
ADM483
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
RO
RE
DE
DI
1
ADM483
2
3
TOP VIEW
(Not to Scale)
4
8
V
CC
B
7
A
6
GND
5
05079-002
Figure 2. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 RO
Receiver Output. When enabled, if A > B by 200 mV, then RO = high.
If A < B by 200 mV, then RO = low.
2
RE Receiver Output Enable. A low level enables the receiver output, RO.
A high level places it in a high impedance state.
3 DE
Driver Output Enable. A high level enables the driver differential inputs A and B.
A low level places it in a high impedance state.
4 DI
Driver Input. When the driver is enabled, a logic low on DI forces A low and B high,
while a logic high on DI forces A high and B low.
5 GND Ground.
6 A Noninverting Receiver Input A/Driver Output A.
7 B Inverting Receiver Input B/Driver Output B.
8 V
CC
5 V Power Supply.
Rev. 0 | Page 6 of 16
Page 7
ADM483
TEST CIRCUITS
V
R
V
OD
R
Figure 3. Driver Voltage Measurement
375Ω
A
0V OR 3V
V
OC
05079-003
DE IN
DE
S1
V
B
C
L
Figure 6. Driver Enable/Disable
R
OUT
CC
L
S2
05079-006
V
V
OD3
60Ω
375Ω
TST
05079-004
Figure 4. Driver Voltage Measurement over Common-Mode Voltage Range
A
R
LDIFF
B
C
L1
C
L2
05079-005
Figure 5. Driver Propagation Delay
A
V
RE
B
OUT
C
L
05079-007
Figure 7. Receiver Propagation Delay
+1.5V
–1.5V
RE IN
S1
RE
C
L
V
CC
R
L
S2
V
OUT
05079-008
Figure 8. Receiver Enable/Disable
Rev. 0 | Page 7 of 16
Page 8
ADM483
3V0V5V0
SWITCHING CHARACTERISTICS
B
VO
A
V
1.5V
t
PLH
1/2VO
t
SKEW
90% POINT
10% POINT
t
R
Figure 9. Driver Propagation Delay, Rise/Fall Timing
0VA, B
=
|t
PLH –tPHL
1.5V
t
PHL
|
t
0V
90% POINT
10% POINT
F
05079-009
DE
A, B
A, B
RE
t
t
1.5V
ZL
2.3V
ZH
2.3V
1.5V
t
LZ
V
OL
t
HZ
V
OH
Figure 11. Driver Enable/Disable Timing
1.5V
t
ZL
1.5V
t
LZ
+0.5V
–0.5V
3V
0V
V
OL
V
OH
0V
05079-011
3V
0V
RO
t
PLH
1.5V 1.5V
t
=
|t
SKEW
PLH –tPHL
t
|
Figure 10. Receiver Propagation Delay
PHL
R
V
OH
R
V
OL
05079-010
0V
1.5V
O/P LOW
t
ZH
O/P HIGH
1.5V
+0.5V
V
OL
t
HZ
V
OH
–0.5V
V
OL
V
OH
05079-012
Figure 12. Receiver Enable/Disable Timing
Rev. 0 | Page 8 of 16
Page 9
ADM483
TYPICAL PERFORMANCE CHARACTERISTICS
400
350
300
0.40
0.35
250
200
DE = V
150
100
UNLOADED SUPPLY CURRENT (µA)
50
0
–50–250 255075100125
TEMPERATURE (
°C)
CC
DE = GND
Figure 13. Supply Current vs. Temperature
50
45
40
35
30
25
20
15
10
RECEIVER OUTPUT CURRENT (mA)
5
0
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
RECEIVER OUTPUT LOW VOLTAGE (V)
Figure 14. Output Current vs. Receiver Output Low Voltage
5
0
–5
–10
–15
RECEIVER OUTPUT CURRENT (mA)
–20
3.5 4.0 4.5 5.0 5.5
RECEIVER OUTPUT HIGH VOLTAGE (V)
Figure 15. Output Current vs. Receiver Output High Voltage
05079-013
05079-014
05079-015
0.30
0.25
OUTPUT LOW VOLTAGE (V)
0.20
0.15
–50 –25 0 25 50 75 100 125
TEMPERATURE (
°
C)
Figure 16. Receiver Output Low Voltage vs. Temperature
4.6
4.5
4.4
4.3
4.2
OUTPUT HIGH VOLTAGE (V)
4.1
4.0
–50–250 255075100125
TEMPERATURE (
°
C)
Figure 17. Receiver Output High Voltage vs. Temperature
90
80
70
60
50
40
30
20
DRIVER OUTPUT CURRENT (mA)
10
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
DIFFERENTIAL OUTPUT VOLTAGE (V)
Figure 18. Driver Output Current vs. Differential Output Voltage
05079-016
05079-017
05079-018
Rev. 0 | Page 9 of 16
Page 10
ADM483
120
800
100
80
60
40
OUTPUT CURRENT (mA)
20
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE (V)
Figure 19. Output Current vs. Driver Output Low Voltage
–10
–30
–50
–70
OUTPUT CURRENT (mA)
–90
–110
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE (V)
Figure 20. Output Current vs. Driver Output High Voltage
05079-019
05079-020
700
600
500
400
300
200
PROPAGATION DELAY (ns)
100
0
–50 –25 0 25 50 75 100 125
TEMPERATURE (°C)
Figure 22. Receiver Propagation Delay vs. Temperature
3
2
4
CH1 1.00VΩ
CH3 2.00VΩ
B
W
B
W
CH2 1.00VΩ
CH4 5.00VΩ
B
W
M400ns CH3 2.00V
Figure 23. Driver/Receiver Propagation Delay
05079-022
05079-023
450
400
350
300
250
200
150
PROPAGATION DELAY (ns)
100
50
0
–50–250 255075100125
TEMPERATURE (
°C)
Figure 21. Driver Propagation Delay vs. Temperature
05079-021
Rev. 0 | Page 10 of 16
Page 11
ADM483
APPLICATIONS
DIFFERENTIAL DATA TRANSMISSION
Differential data transmission is used to reliably transmit
data at high rates over long distances and through noisy
environments. Differential transmission nullifies the effects
of ground shifts and noise signals that appear as commonmode voltages on the line. There are two main standards
approved by the Electronics Industries Association (EIA),
which specify the electrical characteristics of transceivers
used in differential data transmission.
The RS-422 standard specifies data rates up to 10 Mbaud
and line lengths up to 4000 ft. A single driver can drive a
transmission line with up to 10 receivers.
To achieve true multipoint communications, the RS-485
standard was defined. This standard meets or exceeds all the
requirements of RS-422, but also allows up to 32 drivers and 32
receivers to be connected to a single bus. An extended commonmode range of –7 V to +12 V is defined. The most significant
difference between RS-422 and RS-485 is that the drivers may
be disabled, allowing up to 32 to be connected to a single line.
Only one driver should be enabled at a time, but the RS-485
standard contains additional specifications to guarantee device
safety in the event of line contention.
Table 5. Comparison of RS-422 and RS-485 Interface Standards
Specification RS-422 RS-485
Transmission Type Differential Differential
Maximum Cable Length 4000 ft. 4000 ft.
Minimum Driver Output Voltage ±2 V ±1.5 V
Driver Load Impedance 100 Ω 54 Ω
Receiver Input Resistance 4 kΩ min 12 kΩ min
Receiver Input Sensitivity ±200 mV ±200 mV
Receiver Input Voltage Range –7 V to +7 V –7 V to +12 V
Drivers/Receivers per Line 1/10 32/32
CABLE AND DATA RATE
The preferred transmission line for RS-485 communications
is a twisted pair. Twisted pair cable tends to cancel commonmode noise and the magnetic fields generated by the current
flowing through each wire, thereby reducing the effective
inductance of the pair.
The ADM483 is designed for bidirectional data communications on multipoint transmission lines. A typical application
showing a multipoint transmission network is shown in
Figure 24. An RS-485 transmission line can have as many as
32 transceivers on the bus. Only one driver can transmit at a
particular time, but multiple receivers can be enabled simultaneously. As with any transmission line, it is important to
minimize reflections. This can be done by terminating the
extreme ends of the line by using resistors equal to the characteristic impedance of the line. Stub lengths of the main
line should also be kept as short as possible. A properly
terminated transmission line appears purely resistive to
the driver.
RO
RE
DE
DI
ADM483
R
D
A
B
AB
ADM483
R
RO RE DE DI
MAXIMUM NUMBER OF TRANSCEIVERS ON BUS: 32
Figure 24. Typical Half-Duplex RS-485 Network Topology
D
Rev. 0 | Page 11 of 16
ADM483
AB
R
RO RE DE DI
ADM483
A
B
D
R
RO
RE
DE
D
DI
05079-024
Page 12
ADM483
THERMAL SHUTDOWN
The ADM483 contains thermal shutdown circuitry that
protects the part 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 and disables the driver outputs. The thermal sensing
circuitry is designed to disable the driver outputs when a die
temperature of 150°C is reached. As the device cools, the
drivers are re-enabled at 140°C.
RECEIVER OPEN-CIRCUIT FAIL-SAFE
The receiver input includes a fail-safe feature that guarantees
a logic high on the receiver when the inputs are open circuit
or floating.
Rev. 0 | Page 12 of 16
Page 13
ADM483
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
85
6.20 (0.2440)
5.80 (0.2284)
41
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MS-012AA
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
0.25 (0.0098)
0.17 (0.0067)
0.50 (0.0196)
0.25 (0.0099)
8°
1.27 (0.0500)
0°
0.40 (0.0157)
× 45°
Figure 25. 8-Lead Standard Small Outline Package [SOIC]
(R-8)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model Temperature Range Package Description Package Option
ADM483AR –40°C to +85°C 8-Lead Standard Small Outline Package R-8
ADM483AR-REEL –40°C to +85°C 8-Lead Standard Small Outline Package R-8
ADM483AR-REEL7 –40°C to +85°C 8-Lead Standard Small Outline Package R-8
ADM483JR 0°C to 70°C 8-Lead Standard Small Outline Package R-8
ADM483JR-REEL 0°C to 70°C 8-Lead Standard Small Outline Package R-8
ADM483JR-REEL7 0°C to 70°C 8-Lead Standard Small Outline Package R-8
Rev. 0 | Page 13 of 16
Page 14
ADM483
NOTES
Rev. 0 | Page 14 of 16
Page 15
ADM483
NOTES
Rev. 0 | Page 15 of 16
Page 16
ADM483
NOTES
© 2004 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05079-0-10/04(0)
Rev. 0 | Page 16 of 16
Page 17
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
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