Page 1
3.3 V Slew Rate Limited, Half- and
V
V
Data Sheet
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
Full-Duplex, RS-485/RS-422 Transceivers
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
APPLICATIONS
Low power RS-485/RS-422 applications
Te le co m
Industrial process control
HVAC
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 communication, 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 terminated 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 transceivers 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
FUNCTIONAL BLOCK DIAGRAMS
CC
ADM3483/
ADM3485
RO
RE
DE
DI
RO
DI
RO
RE
DE
DI
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.
R
D
GND
Figure 1.
CC
R
ADM3488/
ADM3490
D
GND
Figure 2.
ADM3491
R
D
Figure 3.
A
B
05524-027
A
B
Z
Y
05524-026
A
B
Z
Y
05524-025
Rev. E
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.
Page 2
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
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
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,
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
, DI) Parameter,
RE
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
Page 3
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
Table 1. ADM34xx Part Comparison
Guaranteed
Part No.
ADM3483 0.25 3.0 to 3.6 Half Yes Yes 2 8
ADM3485 10 3.0 to 3.6 Half No Yes 2 8
ADM3488 0.25 3.0 to 3.6 Full Yes No N/A 8
ADM3490 10 3.0 to 3.6 Full No No N/A 8
ADM3491 10 3.0 to 3.6 Full No Yes 2 14
Data Rate (Mbps)
Supply
Voltage (V)
Half-/FullDuplex
Slew Rate
Limited
Driver/Receiver
Enable
Shutdown
Current (nA)
Pin
Count
Rev. E | Page 3 of 20
Page 4
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
SPECIFICATIONS
VCC = 3.3 V ± 0.3 V, TA = T
Table 2.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Output Voltage (VOD) 2.0 V RL = 100 Ω (RS-422), VCC = 3.3 V ± 5% (see Figure 17)
1.5 V RL = 54 Ω (RS-485) (see Figure 17)
1.5 V RL = 60 Ω (RS-485), VCC = 3.3 V (see Figure 18)
∆ |VOD| for Complementary Output States1 0.2 V RL = 54 Ω or 100 Ω (see Figure 17)
Common-Mode Output Voltage (VOC) 3 V RL = 54 Ω or 100 Ω (see Figure 17)
∆ |VOC| for Common-Mode Output Voltage1 0.2 V RL = 54 Ω or 100 Ω (see Figure 17)
DRIVER INPUT LOGIC
CMOS Input Logic Threshold Low (VIL) 0.8 V
CMOS Input Logic Threshold High (VIH) 2.0 V
CMOS Logic Input Current (I
Output Leakage—Y, Z (IO)
Output Leakage (Y, Z) in Shutdown Mode (IO)
RECEIVER
Differential Input Threshold Voltage (VTH) −0.2 +0.2 V −7 V < VCM < +12 V
Input Hysteresis (∆ VTH) 50 mV VCM = 0 V
CMOS Output Voltage High (VOH) VCC – 0.4 V I
CMOS Output Voltage Low (VOL) 0.4 V I
Three-State Output Leakage Current (I
Input Resistance (RIN) 12 kΩ −7 V < VCM < +12 V
POWER SUPPLY CURRENT
Supply Current (ICC)
Supply Current in Shutdown Mode (I
Receiver Short-Circuit Output Current (I
1
∆VOD and ∆VOC are the changes in VOD and VOC, respectively, when DI input changes state.
to T
MIN
)
IN2
, unless otherwise noted.
MAX
DE, DI, RE
DE, DI, RE
) ±2 µA
IN1
DE, DI, RE
1.0 mA VIN = 12 V, DE = 0 V, VCC = 0 V or 3.6 V Input Current—A, B (I
−0.8 mA V
0.1 µA
= −7 V, DE = 0 V, VCC = 0 V or 3.6 V
IN
= 12 V, DE = 0 V, RE = 0 V, VCC = 0 V or 3.6 V,
V
IN
ADM3491 only
−0.1 µA
= −7 V, DE = 0 V, RE = 0 V, VCC = 0 V or 3.6 V,
V
IN
ADM3491 only
0.01 µA
= 12 V, DE = 0 V, RE = VCC, VCC = 0 V or 3.6 V,
V
IN
ADM3491 only
−0.01 µA
= −7 V, DE = 0 V, RE = VCC, VCC = 0 V or 3.6 V,
V
IN
ADM3491 only
= −1.5 mA, VID = 200 mV (see Figure 19)
OUT
= 2.5 mA, VID = 200 mV (see Figure 19)
OUT
) ±1 µA VCC = 3.6 V, 0 V ≤ V
OZR
1.1 2.2 mA
0.95 1.9 mA
) 0.002 1 µA
SHDN
OSD
)
−250 mA V
250 mA V
) ±8 ±60 mA 0 V < VRO < VCC
OSR
DE = V
CC
DE = 0 V, RE = 0 V, no load, DI = 0 V or VCC
DE = 0 V, RE
= −7 V Driver Short-Circuit Output Current (I
OUT
= 12 V
OUT
, RE = 0 V or VCC, no load, DI = 0 V or VCC
= VCC, DI = VCC or 0 V
OUT
≤ VCC
Rev. E | Page 4 of 20
Page 5
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
TIMING SPECIFICATIONS—ADM3485/ADM3490/ADM3491
VCC = 3.3 V, TA = 25°C, unless otherwise noted.
Table 3.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Output Delay (tDD) 1 22 35 ns
Differential Output Transition Time (tTD) 3 8 25 ns
Propagation Delay, Low-to-High Level (t
Propagation Delay, High-to-Low Level (t
|t
– t
| Propagation Delay Skew1 (t
PLH
PHL
DRIVER OUTPUT ENABLE/DISABLE TIMES (ADM3485/
) 7 22 35 ns
PLH
) 7 22 35 ns
PHL
) 8 ns
PDS
ADM3491 ONLY)
Output Enable Time to Low Level (t
Output Enable Time to High Level (t
Output Disable Time from High Level (t
Output Disable Time from Low Level (t
Output Enable Time from Shutdown to Low Level (t
Output Enable Time from Shutdown to High Level (t
1
Measured on |t
PLH
(Y) − t
(Y)| and |t
PHL
PLH
) 45 90 ns
PZL
) 45 90 ns
PZH
) 40 80 ns
PHZ
) 40 80 ns
PLZ
) 650 900 ns
PSL
) 650 900 ns
PSH
(Z) − t
(Z)|.
PHL
RL = 60 Ω (see Figure 20 and Figure 26)
RL = 60 Ω (see Figure 20 and Figure 26)
RL = 27 Ω (see Figure 21 and Figure 27)
RL = 27 Ω (see Figure 21 and Figure 27)
RL = 27 Ω (see Figure 21 and Figure 27)
RL = 110 Ω (see Figure 23 and Figure 29)
RL = 110 Ω (see Figure 22 and Figure 28)
RL = 110 Ω (see Figure 22 and Figure 28)
RL = 110 Ω (see Figure 23 and Figure 29)
RL = 110 Ω (see Figure 23 and Figure 29)
RL = 110 Ω (see Figure 22 and Figure 28)
TIMING SPECIFICATIONS—ADM3483/ADM3488
VCC = 3.3 V, TA = 25°C, unless otherwise noted.
Table 4.
Parameter Min Typ Max Unit Test Conditions/Comments
DRIVER
Differential Output Delay (tDD) 600 900 1400 ns
Differential Output Transition Time (tTD) 400 700 1200 ns
Propagation Delay, Low-to-High Level (t
Propagation Delay, High-to-Low Level (t
|t
– t
| Propagation Delay Skew1 (t
PLH
PHL
) 700 1000 1500 ns
PLH
) 700 1000 1500 ns
PHL
) 100 ns
PDS
DRIVER OUTPUT ENABLE/DISABLE TIMES (ADM3483 ONLY)
Output Enable Time to Low Level (t
Output Enable Time to High Level (t
Output Disable Time from High Level (t
Output Disable Time from Low Level (t
Output Enable Time from Shutdown to Low Level (t
Output Enable Time from Shutdown to High Level (t
1
Measured on |t
PLH
(Y) − t
(Y)| and |t
PHL
PLH
) 900 1300 ns
PZL
) 600 800 ns
PZH
) 50 80 ns
PHZ
) 50 80 ns
PLZ
) 1.9 2.7 µs
PSL
) 2.2 3.0 s
PSH
(Z) − t
(Z)|.
PHL
RL = 60 Ω (see Figure 20 and Figure 26)
RL = 60 Ω (see Figure 20 and Figure 26)
RL = 27 Ω (see Figure 21 and Figure 27)
RL = 27 Ω (see Figure 21 and Figure 27)
RL = 27 Ω (see Figure 21 and Figure 27)
= 110 Ω (see Figure 23 and Figure 29)
R
L
RL = 110 Ω (see Figure 22 and Figure 28)
RL = 110 Ω (see Figure 22 and Figure 28)
RL = 110 Ω (see Figure 23 and Figure 29)
RL = 110 Ω (see Figure 23 and Figure 29)
RL = 110 Ω (see Figure 22 and Figure 28)
Rev. E | Page 5 of 20
Page 6
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
TIMING SPECIFICATIONS—ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
VCC = 3.3 V, TA = 25°C, unless otherwise noted.
Table 5.
Parameter Min Typ Max Unit Test Conditions/Comments
RECEIVER
Time to Shutdown (t
ADM3483/ADM3485/ADM34911 80 190 300 ns
Propagation Delay, Low-to-High Level (t
ADM3485/ADM3490/ADM3491 25 65 90 ns VID = 0 V to 3.0 V, CL = 15 pF (see Figure 24 and Figure 30)
ADM3483/ADM3488 25 75 120 ns
Propagation Delay, High-to-Low Level (t
ADM3485/ADM3490/ADM3491 25 65 90 ns VID = 0 V to 3.0 V, CL = 15 pF (see Figure 24 and Figure 30)
ADM3483/ADM3488 25 75 120 ns
|t
– t
| Propagation Delay Skew (t
PLH
PHL
ADM3485/ADM3490/ADM3491 10 ns VID = 0 V to 3.0 V, CL = 15 pF (see Figure 24 and Figure 30)
ADM3483/ADM3488 20 ns
RECEIVER OUTPUT ENABLE/DISABLE TIMES
(ADM3483/ADM3485/ADM3491 ONLY)
Output Enable Time to Low Level (t
Output Enable Time to High Level (t
Output Disable Time from High Level (t
Output Disable Time from Low Level (t
Output Enable Time from Shutdown to
Low Level (t
PRSL
Output Enable Time from Shutdown to
High Level (t
1
The transceivers are put into shutdown by bringing the RE high and DE low. If the inputs are in this state for less than 80 ns, the parts are guaranteed not to enter
shutdown. If the parts are in this state for 300 ns or more, the parts are guaranteed to enter shutdown.
PRSH
)
SHDN
)
RPLH
)
RPHL
)
RPDS
) 25 50 ns CL = 15 pF (see Figure 25 and Figure 31)
PRZL
) 25 50 ns CL = 15 pF (see Figure 25 and Figure 31)
PRZH
) 25 45 ns CL = 15 pF (see Figure 25 and Figure 31)
PRHZ
) 25 45 ns CL = 15 pF (see Figure 25 and Figure 31)
PRLZ
720 1400 ns CL = 15 pF (see Figure 25 and Figure 31)
)
720 1400 ns C
)
= 15 pF (see Figure 25 and Figure 31)
L
Rev. E | Page 6 of 20
Page 7
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 6.
Parameter Rating
VCC to GND 7 V
Digital I/O Voltage (DE, RE, DI)
Digital I/O Voltage (RO) VCC − 0.5 V to VCC + 0.5 V
Driver Output/Receiver Input Voltage −7.5 V to +12.5 V
Operating Temperature Range −40°C to +85°C
Storage Temperature Range −65°C to +125°C
θJA Thermal Impedance
8-Lead SOIC 121°C/W
14-Lead SOIC 86°C/W
Lead Temperature
Soldering (10 sec) 300°C
Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C
−0.3 V to +6 V
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
Rev. E | Page 7 of 20
Page 8
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
G
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
RO
1
ADM3483/
RE
2
ADM3485
DE
3
TOP VIEW
(Not to Scale)
4
DI
Figure 4. ADM3483/ADM3485 Pin Configuration
V
1
CC
ADM3488/
RO
2
ADM3490
DI
3
TOP VIEW
(Not to Scale)
4
ND
Figure 5. ADM3488/ADM3490 Pin Configuration
NC
1
2
RO
RE
3
ADM3491
TOP VIE W
DE
4
(Not to Scale)
5
DI
GND
6
GND
7
NC = NO CO NNECT
Figure 6. ADM3491 Pin Configuration
V
8
CC
B
7
A
6
5
GND
05524-028
A
8
B
7
Z
6
5
Y
05524-029
V
14
CC
13
V
CC
A
12
B
11
10
Z
Y
9
NC
8
05524-030
Table 7. Pin Function Descriptions
ADM3483/
ADM3485 Pin No.
1 2 2 RO
ADM3488/
ADM3490 Pin No.
ADM3491
Pin No. Mnemonic Description
Receiver Output. When enabled, if A > B by 200 mV, then RO =
high. If A < B by 200 mV, then RO = low.
2 Not applicable 3
Receiver Output Enable. A low level enables the receiver output,
RE
RO. A high level places it in a high impedance state. If RE
is high
and DE is low, the device enters a low power shutdown mode.
3 Not applicable 4 DE
Driver Output Enable. A high level enables the driver differential
Output A and Output B. A low level places it in a high impedance
state. If RE
is high and DE is low, the device enters a low power
shutdown mode.
4 3 5 DI
Driver Input. With a half-duplex part 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. With a full-duplex part when the driver is
enabled, a logic low on DI forces Y low and Z high while a logic
high on DI forces Y high and Z low.
5 4 6, 7 GND Ground.
Not applicable 5 9 Y Noninverting Driver Output.
Not applicable 6 10 Z Inverting Driver Output.
6 Not applicable Not applicable A Noninverting Receiver Input A and Noninverting Driver Output A.
Not applicable 8 12 A Noninverting Receiver Input A.
7 Not applicable Not applicable B Inverting Receiver Input B and Inverted Driver Output B.
Not applicable 7 11 B Inverting Receiver Input B.
8 1 13, 14 V
CC
Power Supply (3.3 V ± 0.3 V).
Not applicable Not applicable 1, 8 NC No Connect.
Rev. E | Page 8 of 20
Page 9
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
–
TYPICAL PERFORMANCE CHARACTERISTICS
30
0.8
25
20
15
10
OUTPUT CURRENT ( mA)
5
0
03
0.51.01.52.02.53.0
OUTPUT VOLTAGE (V)
05524-012
.5
Figure 7. Output Current vs. Receiver Output Low Voltage
16
–14
–12
–10
–8
–6
OUTPUT CURRENT ( mA)
–4
–2
0
03
0.51.01.52.02.53.0
OUTPUT VOLTAGE (V)
05524-013
.5
Figure 8. Output Current vs. Receiver Output High Voltage
3.30
3.25
3.20
3.15
3.10
OUTPUT VOLTAGE (V)
3.05
3.00
–40
–30 –20 –10 0 10 20 30 40 50 60 70 80
TEMPERATURE (°C)
Figure 9. Receiver Output High Voltage vs. Temperature, I
RO
05524-014
= 1.5 mA
0.7
0.6
0.5
0.4
0.3
OUTPUT VOLTAGE (V)
0.2
0.1
0
–40
–30 –20 –10 0 10 20 30 40 50 60 70 80
Figure 10. Receiver Output Low Voltage vs. Temperature, I
100
90
80
70
60
50
40
30
OUTPUT CURRENT ( mA)
20
10
0
03
Figure 11. Driver Output Current vs. Differential Output Voltage
2.6
2.5
2.4
2.3
2.2
2.1
2.0
1.9
OUTPUT VOLTAGE (V)
1.8
1.7
1.6
–40
–30 –20 –10 0 10 20 30 40 50 60 70 80
Figure 12. Driver Differential Output Voltage vs. Temperature, R
TEMPERATURE (°C)
= 2.5 mA
RO
0.51.01.52.02.53.0
OUTPUT VOLTAGE (V)
TEMPERATURE (°C)
05524-015
05524-016
.5
05524-017
= 54 Ω
L
Rev. E | Page 9 of 20
Page 10
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
–
140
120
100
80
60
40
OUTPUT CURRENT ( mA)
20
0
01
246810
OUTPUT VOLTAGE (V)
05524-018
2
Figure 13. Output Current vs. Driver Output Low Voltage
125
–115
–105
–95
–85
–75
–65
–55
–45
–35
OUTPUT CURRENT ( mA)
–25
–15
–5
–7 3
–6 –5 –4 –3 –2 –1 0 1 2
OUTPUT VOLTAGE (V)
05524-019
Figure 14. Output Current vs. Driver Output High Voltage
1.2
1.1
1.0
0.9
0.8
0.7
0.6
SUPPLY CURRENT (mA)
0.5
0.4
0.3
–40
–30 –20 –10 0 10 20 30 40 50 60 70 80
DE = RE = X*
DE = RE = GND
TEMPERATURE (°C)
Figure 15. Supply Current vs. Temperature
90
80
70
60
50
40
30
SHUTDOWN CURRENT ( nA)
20
10
0
–40
–30 –20 –10 0 10 20 30 40 50 60 70 80
TEMPERATURE (°C)
Figure 16. Shutdown Current vs. Temperature
*X = DON’T CARE
05524-020
05524-021
Rev. E | Page 10 of 20
Page 11
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
2
V
TEST CIRCUITS
C
A/Y
B/Z
RL/2
V
OD
V
/2
R
OC
L
05524-003
GENERATOR
1
PPR = 250kHz, 50% DUTY CYCLE,
CL INCLUDES PROBE AND STRAY CAPACITANCE.
1
50
V
CC
D
L
CL= 15pF
t
6.0ns, ZO=50.
R
RL=
60
2
OUT
05524-036
Figure 17. Differential Output Voltage
and Common-Mode Voltage Drivers
375
V
R
OD
D
V
CC
L
375
Figure 18. Differential Output Voltage Drivers
with Varying Common-Mode Voltage
R
V
ID
0
V
OL
I
OL
(+)
VCM=
–7V TO +12V
V
OH
Figure 20. Driver Differential Output Delay and Transition Times
OM
C
1.5V
RL=27
=15pF
L
OUT
2
05524-037
S1
D
GENERATOR
05524-004
1
PPR = 250kHz , 50% DUTY CYCLE,
2
CL INCLUDES PROBE AND S TRAY CAPACITANCE.
1
50
V
CC
V
OH+VOL
=
V
OM
2
t
6.0ns, ZO=50.
R
Figure 21. Driver Propagation Delays
0V OR 3V
GENERATOR
I
OH
(–)
5524-005
1
PPR = 250kHz , 50% DUT Y CYCLE,
2
CL INCLUDES PROBE AND STRAY CAPACITANCE.
1
50
D
S1
2
C
= 50pF
L
V
OH+VOL
=
V
OM
2
t
6.0ns, ZO=50.
R
1.5V
OUT
RL= 110
05524-038
Figure 19. CMOS Output Voltage High and
Figure 22. Driver Enable and Disable Times (t
PZH
, t
, t
)
PSH
PHZ
CMOS Output Voltage Low Receivers
Rev. E | Page 11 of 20
Page 12
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
V
2
0V OR 3V
GENERATOR
1
PPR = 250kHz , 50% DUT Y CYCLE,
2
CL INCLUDES PROBE AND STRAY CAPACITANCE.
1
D
50
Figure 23. Driver Enable and Disable Times (t
1.5V
1
50
0
GENERATOR
1
PPR = 250kHz, 50% DUTY CYCLE,
CL INCLUDES PROBE AND STRAY CAPACITANCE.
Figure 24. Receiver Propagation Delays
S1
C
= 50pF
L
t
6.0ns, ZO=50.
R
V
ID
R
t
6.0ns, ZO=50.
R
2
OUT
VOM=
CC
, t
PZL
C
RL=110
OUT
, t
PSL
PLZ
=15pF
L
V
CC
2
+1.5V
–1.5V
1
PPR = 250kHz, 50% DUT Y CYCLE,
2
CL INCLUDES PROBE AND ST RAY CAPACITANCE.
05524-039
S3
V
R
ID
C
L
GENERATOR
1
50
t
6.0ns, ZO=50.
R
Figure 25. Receiver Enable and Disable Times
1k
2
S1
S2
V
CC
05524-041
)
2
05524-040
Rev. E | Page 12 of 20
Page 13
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
V
V
V
V
V
V
V
SWITCHING CHARACTERISTICS
IN
OUT
1.5V 1.5V
t
DD
t
TD
t
DD
90%90%
50%50%
10%10%
t
TD
Figure 26. Driver Differential Output Delay and Transition Times
IN
A/Y
OUT
B/Z
OUT
1.5V 1.5V
t
PLH
V
OM
t
PHL
V
OM
t
PHL
V
OM
t
PLH
V
OM
Figure 27. Driver Propagation Delays
t
PRZH
PRSH
1.5V
1.5V
IN
t
OUT
+3
0
+2V
–2V
05524-006
3
0V
V
OH
V
OL
V
OH
V
OL
05524-007
1.5V1.5V
V
OM
OUT
IN
t
RPLH
Figure 30. Receiver Propagation Delays
+3
S1 OPEN
S2 CLOSED
S3 = +1.5V
0
V
OH
0
OUT
IN
OUT
t
PZH
t
PHZ
V
OM
Figure 28. Driver Enable and Disable Times (t
IN
OUT
1.5V 1. 5V
t
PSL
V
OM
Figure 29. Driver Enable and Disable Times (t
3
0
t
RPHL
V
V
OM
IN
CC
0
05524-010
1.5V
t
PRZL
t
PRSL
1.5V
1.5V1.5V
+3
0
V
CC
V
OL
t
PLZ
S1 CLOSED
S2 OPEN
S3 = –1.5V
0.25V
0.25V
PZH
3
0
V
OH
0
05524-008
, t
, t
)
PSH
PHZ
3
0
V
CC
V
OL
05524-009
, t
, t
PZL
)
PSL
PLZ
+3V
0
V
V
CC
OL
S1 CLOSED
S2 OPEN
S3 = –1.5V
5524-011
OUT
IN
+0.25V
1.5V
t
PRHZ
+3V
0
V
0
OH
S1 OPEN
S2 CLOSED
S3 = +1.5V
OUT
IN
+0.25V
1.5V
t
PRLZ
Figure 31. Receiver Enable and Disable Times
Rev. E | Page 13 of 20
Page 14
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
CIRCUIT DESCRIPTION
The ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 are
low power transceivers for RS-485 and RS-422 communications.
The ADM3483/ADM3488 transmit and receive at data rates up
to 250 kbps; the ADM3485/ADM3490/ADM3491 transmit at up to
10 Mbps. The ADM3488/ADM3490/ADM3491 are full-duplex
transceivers, while the ADM3483/ADM3485 are half-duplex
transceivers. Driver enable (DE) and receiver enable (
RE
) pins
are included on the ADM3483/ADM3485/ADM3491. When
disabled, the driver and receiver outputs are high impedance.
DEVICES WITH RECEIVER/DRIVER ENABLES (ADM3483/ADM3485/ADM3491)
Table 8. Transmitting Truth Table
Transmitting Input Transmitting Output
DE DI B1 A
RE
X2 1 1 0 1 Normal
X2 1 0 1 0 Normal
0 0 X2 High-Z3 High-Z3 Normal
1 0 X2 High-Z3 High-Z3 Shutdown
1
A and B outputs are Y and Z, respectively, for full-duplex part (ADM3491).
2
X = don’t care.
3
High-Z = high impedance.
Table 9. Receiving Truth Table
Receiving Input Receiving Output
DE1 A – B RO
RE
0 0 ≥ +0.2 V 1 Normal
0 0 ≤ −0.2 V 0 Normal
0 0 Inputs Open 1 Normal
1 0 X2 High-Z3 Shutdown
1
DE is a don’t care; X for the full-duplex part (ADM3491).
2
X = don’t care.
3
High-Z = high impedance.
1
Mode
Mode
REDUCED EMI AND REFLECTIONS (ADM3483/ADM3488)
The ADM3483/ADM3488 are slew rate limited transceivers,
minimizing EMI and reducing reflections caused by improperly
terminated cables.
LOW POWER SHUTDOWN MODE (ADM3483/ADM3485/ADM3491)
A low power shutdown mode is initiated by bringing RE high
and DE low. The devices do not shut down unless both the driver
and receiver are disabled (high impedance). In shutdown mode,
the devices typically draw only 2 nA of supply current. For these
devices, the t
low power shutdown mode; the t
PSH
and t
enable times assume the part is in the
PSL
and t
PZH
enable times assume
PZL
the receiver or driver was disabled, but the part is not shut down.
DRIVER OUTPUT PROTECTION
Two methods are implemented to prevent excessive output current
and power dissipation caused by faults or by bus contention.
Current limit protection on the output stage provides immediate
protection against short circuits over the whole common-mode
voltage range (see the Ty pical Performance C h a r acteristi c s section).
In addition, a thermal shutdown circuit forces the driver outputs
into a high impedance state if the die temperature rises
excessively.
PROPAGATION DELAY
Skew time is the difference between the low-to-high and highto-low propagation delays. Small driver/receiver skew times help
maintain a symmetrical mark-space ratio (50% duty cycle).
The receiver skew time (|t
for ADM3483/ADM3488). The driver skew times are 8 ns for
ADM3485/ADM3490/ADM3491 and typically under 100 ns for
ADM3483/ADM3488.
PRLH
− t
|) is under 10 ns (20 ns
PRHL
DEVICES WITHOUT RECEIVER/DRIVER ENABLES— ADM3488/ADM3490
TYPICAL APPLICATIONS
The ADM3483/ADM3485/ADM3491 transceivers are designed
for half-duplex bidirectional data communications on multipoint
Table 10. Transmitting Truth Table
Transmitting Input Transmitting Output
DI Z Y
1 0 1
0 1 0
bus transmission lines, Figure 32 and Figure 33 show typical
network applications circuits. The ADM3488 and the ADM3490
full-duplex transceivers are designed to be used in a daisy-chain
network topology or in a point-to-point application, see Figure 34
and Figure 35. The ADM3491 can be used as line repeat Figure 36.
To minimize reflections, the line must be terminated at both
Table 11. Receiving Truth Table
Receiving Input Receiving Output
A – B RO
≥ +0.2 V 1
≤ −0.2 V 0
Inputs open 1
ends in its characteristic impedance, and stub lengths off the main
line must be kept as short as possible. The slew rate limited
ADM3483/ADM3488 are more tolerant of imperfect termination.
Rev. E | Page 14 of 20
Page 15
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
R
LINE LENGTH vs. DATA RATE
The RS-485 and RS-422 standards cover line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 36.
MAXIMUM NUMBER OF TRANSCEIVERS ON BUS = 32
A
B
A
B
ADM3483/
ADM3485
R
A
T
B
ADM3483/
ADM3485
R
D
RO
RE
DE
DI
RO
RE
DE
DI
ADM3483/
ADM3485
R
D
V
CC
A
R
T
B
R1
R2
ADM3483/
ADM3485
R
RO
RE DI
NOTES
1. R
IS EQUAL T O THE CHARACTERISTIC IM PEDANCE OF THE CABLE.
T
D
DE
RO
R
RE
DE
D
DI
05524-022
Figure 32. ADM3483/ADM3485 Typical Half-Duplex RS-485 Network
MAXIMUM NUMBER O F NODES = 32
A B Z Y
D
R
D
R1
R
T
V
CC
R2
SLAVE
ADM3491
SLAVE
Y
R
T
Z
B
A
D
R
DI
DE
RE
RO
ADM3491
RO
DE
RE
DI
MASTER
R
D
ADM3491
V
CC
A
R
T
B
Z
R
T
Y
SLAVE
ADM3491
R1
R2
A B Z Y
R
RO DIDE
RE
NOTES
IS EQUAL T O THE CHARACTERISTIC IM PEDANCE OF T HE CABLE.
1.
T
RO DIDE
RE
05524-090
Figure 33. ADM3491 Typical Full-Duplex RS-485 Network
Rev. E | Page 15 of 20
Page 16
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
RO
ADM3488/
ADM3490
DI
MASTER
R
D
A
B
Z
Y
ADM3488/
ADM3490
SLAVE
ABZY ABZY
R
D
RO
R
D
DI RO DI
ADM3488/
ADM3490
Y
Z
B
A
ADM3488/
ADM3490
SLAVE
SLAVE
R
D
DI
RO
05524-042
Figure 34. ADM3488/ADM3490 Full-Duplex Daisy-Chain Network
Y
Z
B
A
SLAVE
ADM3488/
ADM3490
D
R
DI
RO
5524-043
MASTER
ADM3488/
RO
DI
ADM3490
R
D
A
B
Z
Y
Figure 35. ADM3488/ADM3490 Full-Duplex Point-to-Point Applications
ADM3491
RO
RE
DE
DI
NOTES
IS EQUAL T O THE CHARACTERISTIC IMPEDANCE OF THE CABLE.
1. R
T
R
D
A
DATA IN
R
T
B
Z
DATA OUT
R
T
Y
05524-091
Figure 36. Line Repeater for ADM3491
Rev. E | Page 16 of 20
Page 17
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
0.25 (0.0098)
0.10 (0.0040)
COPLANARITY
0.10
CONTROLLING DIMENSIONS ARE IN MIL LIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
85
1
1.27 (0.0500)
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MS-012-AA
BSC
6.20 (0.2441)
5.80 (0.2284)
4
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
8°
0°
0.25 (0.0098)
0.17 (0.0067)
0.50 (0.0196)
0.25 (0.0099)
1.27 (0.0500)
0.40 (0.0157)
45°
012407-A
Figure 37. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
8.75 (0.3445)
8.55 (0.3366)
BSC
8
7
6.20 (0.2441)
5.80 (0.2283)
1.75 (0.0689)
1.35 (0.0531)
SEATING
PLANE
8°
0°
0.25 (0.0098)
0.17 (0.0067)
0.50 (0.0197)
0.25 (0.0098)
1.27 (0.0500)
0.40 (0.0157)
45°
4.00 (0.1575)
3.80 (0.1496)
0.25 (0.0098)
0.10 (0.0039)
COPLANARIT Y
0.10
14
1
1.27 (0.0500)
0.51 (0.0201)
0.31 (0.0122)
CONTROLL ING DIM ENSIONS ARE IN MILL IMETE RS; INCH DIMENS IONS
(IN PARENTHESES) ARE RO UNDED-OFF MILLI METER EQ UIVALENTS FOR
REFERENCE ON LY AND ARE NOT APPROPRIATE FOR USE I N DESIGN.
COMPLIANT T O JEDEC STANDARDS MS-012- AB
060606-A
Figure 38. 14-Lead Narrow Body Small Outline [SOIC_N]
Narrow Body
(R-14)
Dimensions shown in millimeters and (inches)
Rev. E | Page 17 of 20
Page 18
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option Ordering Quantity
ADM3483ARZ
ADM3483ARZ–REEL7
ADM3485ARZ
ADM3485ARZ–REEL7
ADM3488ARZ
ADM3488ARZ–REEL7
ADM3490ARZ
ADM3490ARZ–REEL7
ADM3491AR −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14
ADM3491AR-REEL −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14 2,500
ADM3491AR-REEL7 −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14 1,000
ADM3491ARZ −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14
ADM3491ARZ-REEL −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14 2,500
ADM3491ARZ-REEL7 −40°C to +85°C 14-Lead Narrow Body Small Outline (SOIC_N) R-14 1,000
1
Z = RoHS Compliant Part.
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
8-Lead Narrow Body Small Outline (SOIC_N) R-8
8-Lead Narrow Body Small Outline (SOIC_N) R-8 1,000
8-Lead Narrow Body Small Outline (SOIC_N) R-8
8-Lead Narrow Body Small Outline (SOIC_N) R-8 1,000
8-Lead Narrow Body Small Outline (SOIC_N) R-8
8-Lead Narrow Body Small Outline (SOIC_N) R-8 1,000
8-Lead Narrow Body Small Outline (SOIC_N) R-8
8-Lead Narrow Body Small Outline (SOIC_N) R-8 1,000
Rev. E | Page 18 of 20
Page 19
Data Sheet ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
NOTES
Rev. E | Page 19 of 20
Page 20
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491 Data Sheet
NOTES
©2005-2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05524-0-11/11(E)
Rev. E | Page 20 of 20
Page 21
Mouser Electronics
Authorized Distributor
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