PRELIMINARY TECHNICAL DATA
a
Low-Current (1nA) Shutdown Mode
High-Speed (10Mbps), Fail-Safe, RS-485/RS-422
Transceivers with Slew-Rate-Limiting
and ±15kV ESD Protection
ADM3082/ADM3085/ADM3088
GENERAL DESCRIPTION
FEATURES
Enhanced Slew Rate Limiting for Error-Free Data
Transmission
Fail-Safe Receiver Operation while Maintaining
EIA/TIA-485 compatibility
High Input Impedance — Up to 256 Transceivers on Bus
±15kV ESD Protection (Human Body Model) on
RS-485 I/O pins
Pin-Compatible with Industry Standard 75176
APPLICATIONS
Enhanced Replacement for Industry-Standard Parts
EMI-Sensitive Systems
Level Translation
LANs for Industrial Control Applications
The ADM3082/ADM3085/ADM3088 are high-speed
RS-485/RS-422 transceivers consisting of one driver and one
receiver per package. The devices feature fail-safe operation,
ensuring a logic-high receiver output when the receiver in-
puts are open-circuit or short-circuit. This guarantees that
the receiver output will be high if all the transmitters on a
terminated bus are disabled (high-impedance).
The ADM3082 has a slew-rate limited driver to minimize
electromagnetic interference (EMI) and reduce reflections
caused by incorrectly terminated cables. This allows error-
free transmission at data rates up to 115kbps.
The ADM3085 offers a higher slew rate allowing data rates
up to 500kbps, while the ADM3088 has a driver whose slew
rate is not limited, allowing data rates up to 10Mbps.
All devices in the family feature ±15kV electrostatic dis-
charge (ESD) protection and high receiver input imped-
ance (1/8 unit load), allowing up to 256 transceivers on
the bus. The devices have low current drain of 375µA un-
loaded, or fully loaded with the drivers disabled, and fea-
ture an ultra-low power (1nA) shutdown mode.
FUNCTIONAL BLOCK DIAGRAM
RO
RE
DE
DI
1
R
2
3
4
D
8
7
6
5
V
CC
B
A
G ND
AD M 30 82/A D M 308 5/AD M 3088
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
World Wide Web Site: http://www.analog.com
Fax: 617/326-8703
© Analog Devices, Inc., 2002
PRELIMINARY TECHNICAL DATA
ADM3082/ADM3085/ADM3088
ADM3082/ADM3085/ADM3088 SPECIFICATIONS
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 1)
DRIVER
Parameter
Differential Driver Output, V
OD1
Differential Driver Output,V
OD2
Change-in-Magnitude of Differential
Common-Mode Output Voltage, V
OD
Driver Common-Mode
Output Voltage, V
OC
Change-in-Magnitude of
Common-Mode Voltage,
Input High Voltage,V
IH1
(DE, DI,
RE)
Input Low Voltage, V
lL1
(DE, DI,
RE)
DI Input Hysteresis, V
HYS
Input Current, I
IN1
(DE, DI,
RE)
Input Current (A and B), I
IN4
100
±2
125
–75
Output Leakage (Y and Z),
Full Duplex, I
O
–100
Driver Short-Circuit,V
OD1
Output Current
±25
–250
250
125
V
OC
2.0
0.8
V
V
mV
µA
µA
µA
µA
µA
mA
mA
mA
DE
V
IN
DE
V
IN
DE
V
IN
DE
V
IN
–7V
0V
0V
=
=
=
=
=
=
=
=
GND, V
CC
= GND or 5.25V,
12V
GND, V
CC
= GND or 5.25V,
–7V
GND, V
CC
= GND or 5.25V,
12V
GND, V
CC
= GND or 5.25V,
–7V
V
OUT
V
OUT
V
OUT
V
CC
(Note 3)
12V (Note 3)
V
CC
(Note 3)
2.0
1.5
0.2
3
0.2
Min
Typ
Max
5
Units Test Conditions/Comments
V
V
V
V
V
V
Figure 1 (No Load)
Figure 1, R = 50
Figure 1, R = 27
Figure 1, R = 50
(Note 2)
Figure 1, R = 50
Figure 1, R = 50
(Note 2)
(RS-422)
(RS-485)
or R = 27
or R = 27
or R = 27
–2–
PRELIMINARY TECHNICAL DATA
ADM3082/ADM3085/ADM3088
ADM3082/ADM3085/ADM3088 SPECIFICATIONS (continued)
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 1)
RECEIVER
Parameter
Receiver Differential Threshold
Voltage, V
TH
Receiver Input Hysteresis,
V
TH
V
CC
–1 .5
0.4
±1
96
±7
±95
Min
–200
Typ
–125
25
Max
–50
Units Test Conditions/Comments
mV
mV
V
V
µA
k
mA
I
O
= -4mA, V
ID
= -50mV
I
O
= 4mA, V
ID
= -200mV
0.4V
–7V
0V
V
O
V
CM
V
RO
2.4V
12V
V
CC
–7V
V
CM
12V
Receiver Output High Voltage, V
OH
Receiver Output Low Voltage, V
OL
Three-State Output Current at
Receiver, I
OZR
Receiver Input Resistance, R
IN
Receiver Output Short-Circuit
Current, I
OSR
SUPPLY CURRENT
Parameter
Supply Current, I
CC
Min
Typ
430
375
Supply Current in
Shutdown Mode, I
SHDN
ESD Protection for Y, Z, A, B
NOTES
1
2
Max
900
600
10
Units Test Conditions/Comments
µA
µA
µA
kV
No
DE
No
DE
load,
RE
= DI = GND or V
CC
,
= V
CC
load,
RE
= DI = GND or V
CC
,
= GND
0.001
±15
DE = GND, V
RE
= V
CC
Human Body Model
All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device ground unless otherwise noted.
DO
and V
CC
are the changes in V
OD
and V
OC
, respectively, when the DI input changes state.
3
Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during current limiting.
–3–
PRELIMINARY TECHNICAL DATA
ADM3082/ADM3085/ADM3088
ADM3082/ADM3085/ADM3088 SPECIFICATIONS (continued)
SWITCHING CHARACTERISTICS—ADM3082
(V
CC
= +5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 1)
Parameter
Driver Input-to-Output, t
DPLH
Driver Input-to-Output, t
DPHL
Driver Output Skew,|t
DPLH
-t
DPHL
|, t
DSKEW
Driver Rise or Fall Time, t
DR
, t
DF
Maximum Data Rate, f
MAX
Driver Enable to Output High, t
DZH
Driver Enable to Output Low, t
DZL
Driver Disable Time from Low, t
DLZ
Driver Disable Time from High, t
DHZ
Receiver Input to Output, t
RPLH
, t
RPHL
Differential Receiver Skew, t
RSKD
|t
RPLH
- t
RPHL
|
Receiver Enable to Output Low, t
RZL
Receiver Enable to Output High, t
RZH
Receiver Disable Time from Low, t
RLZ
Receiver Disable Time from High, t
RHZ
Time to Shutdown, t
SHDN
Driver Enable from Shutdown to
Output High, t
DZH(SHDN)
Driver Enable from Shutdown to
Output Low, t
DZL(SHDN)
Receiver Enable from Shutdown
to Output High, t
RZH(SHDN)
Receiver Enable from Shutdown
to Output Low, t
RZL(SHDN)
50
127
3
20
20
20
20
200
667
115
3500
3500
100
100
200
±30
50
50
50
50
600
6000
6000
3500
3500
Min
500
500
Typ
2030
2030
–3
1320
Max
2600
2600
±200
2500
Units Test Conditions/Comments
ns
ns
ns
ns
kbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Figures 5 and 6, C
L
= 100pF,
S2 closed
Figures 5 and 6, C
L
= 100pF,
S1 closed
Figures 5 and 6, C
L
= l5pF,
S1 closed
Figures 4 and 5, C
L
= l5pF,
S2 closed
Figure 7; |V
ID
|
2.0V;
rise and fall time of V
ID
Figure 7; |V
ID
|
2.0V;
rise and fall time of V
ID
l5ns
l5ns
Figures 2 and 3, R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 2 and 3, R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 2 and 3, R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 7 and 8; C
L
= 100pF,
S1 closed
Figures 7 and 8, C
L
= 100pF,
S2 closed
Figures 7 and 8, C
L
= 100pF,
S1 closed
Figures 7 and 8 C
L
= 100pF,
S2 closed
(Note 5)
Figures 5 and 6, C
L
= l5pF,
S2 closed
Figures 5 and 6, C
L
= l5pF,
S1 closed
Figures 7 and 8, C
L
= 100pF,
S2 closed
Figures 7 and 8, C
L
= 100pF,
S1 closed
–4–
PRELIMINARY TECHNICAL DATA
ADM3082/ADM3085/ADM3088
ADM3082/ADM3085/ADM3088 SPECIFICATIONS (continued)
SWITCHING CHARACTERISTICS—ADM3085
(V
CC
= +5V ±5%, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
CC
= +5V and T
A
= +25°C.) (Note 1)
Parameter
Driver Input-to-Output, t
DPLH
Driver Input-to-Output, t
DPHL
Driver Output Skew,|t
DPLH
- t
DPHL
|, t
DSKEW
Driver Rise or Fall Time, t
DR
, t
DF
Maximum Data Rate, f
MAX
Driver Enable to Output High, t
DZH
Driver Enable to Output Low, t
DZL
Driver Disable Time from Low, t
DLZ
Driver Disable Time from High, t
DHZ
Receiver Input to Output, t
RPLH
, t
RPHL
Differential Receiver Skew, t
RSKD
|t
RPLH
- t
RPHL
|
Receiver Enable to Output Low, t
RZL
Receiver Enable to Output High, t
RZH
Receiver Disable Time from Low, t
RLZ
Receiver Disable Time from High, t
RHZ
Time to Shutdown, t
SHDN
Driver Enable from Shutdown
to Output High, t
DZH(SHDN)
Driver Enable from Shutdown
to Output Low, t
OZL(SHDN)
Receiver Enable from Shutdown
to Output High, t
RZH(SHDN)
Receiver Enable from Shutdown
to Output Low, t
RZL(SHDN)
50
127
3
20
20
20
20
200
200
500
2500
2500
100
100
200
±30
50
50
50
50
600
4500
4500
3500
3500
Min
250
250
Typ
720
720
–3
530
Max
1000
1000
±100
750
Units Test Conditions/Comments
ns
ns
ns
ns
kbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Figures 5 and 6, C
L
= 100pF,
S2 closed
Figures 5 and 6, C
L
= 100pF,
S1 closed
Figures 5 and 6, C
L
= l5pF,
S1 closed
Figures 5 and 6, C
L
= l5pF,
S2 closed
Figure 7; |V
ID
|
2.0V;
rise and fall time of V
ID
Figure 7; |V
ID
|
2.0V;
rise and fall time of V
ID
l5ns
l5ns
Figures 2 and 3 R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 2 and 3, R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 2 and 3, R
DIFF
= 54 ,
C
L1
= C
L2
= 100pF
Figures 7 and 8 C
L
= 100pF,
S1 closed
Figures 7 and 8, C
L
= 100pF,
S2 closed
Figures 7 and 8, C
L
= 100pF,
S1 closed
Figures 7 and 8, C
L
= 100pF,
S2 closed
(Note 5)
Figures 5 and 6, C
L
= l5pF,
S2 closed
Figures 5 and 6, C
L
= l5pF,
S1 closed
Figures 7 and 8, C
L
= 100pF,
S2 closed
Figures 7 and 8, C
L
= 100pF,
S1 closed
–5–
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