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3.3 V Slew Rate Limited, Half- and
Full-Duplex, RS-485/RS-422 Transceivers
Data Sheet
FEATURES
Operate with 3.3 V supply
Interoperable with 5 V logic
EIA RS-422 and RS-485 compliant over full
common-mode range
Data rate options
ADM3483/ADM3488: 250 kbps
ADM3485/ADM3490/ADM3491: 10 Mbps
Half- and full-duplex options
Reduced slew rates for low EMI (ADM3483 and ADM3488)
2 nA supply current in shutdown mode
(ADM3483/ADM3485/ADM3491)
Up to 32 transceivers on the bus
−7 V to +12 V bus common-mode range
Specified over the –40°C to +85°C temperature range
8 ns skew (ADM3485/ADM3490/ADM3491)
8-lead SOIC and 14-lead SOIC (ADM3491 only) packages
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
FUNCTIONAL BLOCK DIAGRAMS
V
CC
ADM3483/
ADM3485
RO
RE
DE
DI
D
R
A
B
05524-027
GND
Figure 1.
V
CC
A
B
RO
R
APPLICATIONS
Low power RS-485/RS-422 applications
Telecom
Industrial process control
HVAC
DI
ADM3488/
ADM3490
Z
Y
GND
05524-026
05524-025
D
Figure 2.
GENERAL DESCRIPTION
The ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 are
low power, differential line transceivers designed to operate using a
single 3.3 V power supply. Low power consumption, coupled with a
shutdown mode, makes the ADM3483/ADM3485/ADM3488/
ADM3490/ADM3491 ideal for power-sensitive applications.
The ADM3488/ADM3490/ADM3491 feature full-duplex com-
munication, while the ADM3483/ADM3485 are designed for
half-duplex communication.
The ADM3483/ADM3488 feature slew rate limited drivers that
minimize EMI and reduce reflections caused by improperly ter-
minated cables, allowing error-free data transmission at data rates
up to 250 kbps.
The ADM3485/ADM3490/ADM3491 transmit at up to 10 Mbps.
The receiver input impedance is 12 kΩ, allowing up to 32 trans-
ceivers to be connected on the bus. A thermal shutdown circuit
prevents excessive power dissipation caused by bus contention or
by output shorting. If a significant temperature increase is detected
RO
RE
DE
DI
ADM3491
R
A
B
Z
D
Y
Figure 3.
in the internal driver circuitry during fault conditions, then the
thermal shutdown circuit forces the driver output into a high
impedance state. If the inputs are unconnected (floating), the
receiver contains a fail-safe feature that results in a logic high
output state. The parts are fully specified over the commercial
and industrial temperature ranges. The ADM3483/ADM3485/
ADM3488/ADM3490 are available in 8-lead SOIC_N; the
ADM3491 is available in a 14-lead SOIC_N.
Rev. E
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 ©2005-2011 Analog Devices, Inc. All rights reserved.
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagrams............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 4
Timing Specifications—ADM3485/ADM3490/ADM3491.... 5
Timing Specifications—ADM3483/ADM3488........................ 5
Timing Specifications—
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 ...... 6
Absolute Maximum Ratings............................................................ 7
ESD Caution.................................................................................. 7
Pin Configurations and Function Descriptions ........................... 8
Typical Performance Characteristics ............................................. 9
Test Circuits..................................................................................... 11
Data Sheet
Switching Characteristics .............................................................. 13
Circuit Description......................................................................... 14
Devices with Receiver/Driver Enables
(ADM3483/ADM3485/ADM3491)......................................... 14
Devices Without Receiver/Driver Enables—
ADM3488/ADM3490................................................................ 14
Reduced EMI and Reflections (ADM3483/ADM3488) ....... 14
Low Power Shutdown Mode
(ADM3483/ADM3485/ADM3491)......................................... 14
Driver Output Protection.......................................................... 14
Propagation Delay ...................................................................... 14
Typical Applications................................................................... 14
Line Length vs. Data Rate ......................................................... 15
Outline Dimensions ....................................................................... 17
Ordering Guide .......................................................................... 18
REVISION HISTORY
11/11—Rev. D to Rev. E
Changes to Digital I/O Voltage (DE, RE, DI) Parameter,
Table 6 ................................................................................................ 7
Moved Typical Performance Characteristics Section .................. 9
Moved Test Circuits Section.......................................................... 11
Moved Switching Characteristics Section ................................... 13
Changes to Note 1, Table 8 ............................................................ 14
Changes to Outline Dimensions................................................... 17
12/10—Rev. C to Rev. D
Changes to Figure 33...................................................................... 15
8/10—Rev. B to Rev. C
Changes to Table 2, Driver Input Logic......................................... 4
10/06—Rev. A to Rev. B
Updated Format..................................................................Universal
Added ADM3491 ...............................................................Universal
Changes to Specifications Section...................................................4
Changes to Typical Applications Section .................................... 14
7/06—Rev. 0 to Rev. A
Changes to Applications ...................................................................1
Changes to General Description .....................................................1
Changes to Figure 19...................................................................... 10
Changes to Typical Applications Section .................................... 13
Changes to Figure 31 and Figure 32............................................. 14
Updated Outline Dimensions....................................................... 15
10/05—Revision 0: Initial Version
Rev. E | Page 2 of 20
Data Sheet
Table 1. ADM34xx Part Comparison
Part No.
ADM3483
ADM3485
ADM3488
ADM3490
ADM3491
Guaranteed
Data Rate (Mbps)
0.25
10
0.25
10
10
Supply
Voltage (V)
3.0 to 3.6
3.0 to 3.6
3.0 to 3.6
3.0 to 3.6
3.0 to 3.6
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
Half-/Full-
Duplex
Half
Half
Full
Full
Full
Slew Rate
Limited
Yes
No
Yes
No
No
Driver/Receiver
Enable
Yes
Yes
No
No
Yes
Shutdown
Current (nA)
2
2
N/A
N/A
2
Pin
Count
8
8
8
8
14
Rev. E | Page 3 of 20
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
SPECIFICATIONS
V
CC
= 3.3 V ± 0.3 V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
Table 2.
Parameter
DRIVER
Differential Output Voltage (V
OD
)
Min
2.0
1.5
1.5
0.2
3
0.2
0.8
2.0
±2
1.0
−0.8
0.1
−0.1
Output Leakage (Y, Z) in Shutdown Mode (I
O
)
0.01
−0.01
RECEIVER
Differential Input Threshold Voltage (V
TH
)
Input Hysteresis (Δ V
TH
)
CMOS Output Voltage High (V
OH
)
CMOS Output Voltage Low (V
OL
)
Three-State Output Leakage Current (I
OZR
)
Input Resistance (R
IN
)
POWER SUPPLY CURRENT
Supply Current (I
CC
)
Supply Current in Shutdown Mode (I
SHDN
)
Driver Short-Circuit Output Current (I
OSD
)
Receiver Short-Circuit Output Current (I
OSR
)
1
Data Sheet
Typ
Max
Unit
V
V
V
V
V
V
V
V
μA
mA
mA
μA
μA
μA
μA
Test Conditions/Comments
R
L
= 100 Ω (RS-422), V
CC
= 3.3 V ± 5% (see Figure 17)
R
L
= 54 Ω (RS-485) (see Figure 17)
R
L
= 60 Ω (RS-485), V
CC
= 3.3 V (see Figure 18)
R
L
= 54 Ω or 100 Ω (see Figure 17)
R
L
= 54 Ω or 100 Ω (see Figure 17)
R
L
= 54 Ω or 100 Ω (see Figure 17)
DE, DI, RE
DE, DI, RE
DE, DI, RE
V
IN
= 12 V, DE = 0 V, V
CC
= 0 V or 3.6 V
V
IN
= −7 V, DE = 0 V, V
CC
= 0 V or 3.6 V
V
IN
= 12 V, DE = 0 V, RE = 0 V, V
CC
= 0 V or 3.6 V,
ADM3491 only
V
IN
= −7 V, DE = 0 V, RE = 0 V, V
CC
= 0 V or 3.6 V,
ADM3491 only
V
IN
= 12 V, DE = 0 V, RE = V
CC
, V
CC
= 0 V or 3.6 V,
ADM3491 only
V
IN
= −7 V, DE = 0 V, RE = V
CC
, V
CC
= 0 V or 3.6 V,
ADM3491 only
−7 V < V
CM
< +12 V
V
CM
= 0 V
I
OUT
= −1.5 mA, V
ID
= 200 mV (see Figure 19)
I
OUT
= 2.5 mA, V
ID
= 200 mV (see Figure 19)
V
CC
= 3.6 V, 0 V ≤ V
OUT
≤ V
CC
−7 V < V
CM
< +12 V
DE = V
CC
, RE = 0 V or V
CC
, no load, DI = 0 V or V
CC
DE = 0 V, RE = 0 V, no load, DI = 0 V or V
CC
DE = 0 V, RE = V
CC
, DI = V
CC
or 0 V
V
OUT
= −7 V
V
OUT
= 12 V
0 V < V
RO
< V
CC
Δ |V
OD
| for Complementary Output States
1
Common-Mode Output Voltage (V
OC
)
Δ |V
OC
| for Common-Mode Output Voltage
1
DRIVER INPUT LOGIC
CMOS Input Logic Threshold Low (V
IL
)
CMOS Input Logic Threshold High (V
IH
)
CMOS Logic Input Current (I
IN1
)
Input Current—A, B (I
IN2
)
Output Leakage—Y, Z (I
O
)
−0.2
50
V
CC
– 0.4
+0.2
0.4
±1
12
1.1
0.95
0.002
2.2
1.9
1
−250
250
±60
V
mV
V
V
μA
kΩ
mA
mA
μA
mA
mA
mA
±8
∆V
OD
and
∆V
OC
are the changes in V
OD
and V
OC
, respectively, when DI input changes state.
Rev. E | Page 4 of 20
ADI Reference Circuit
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