3.3 V Slew Rate Limited, Half- and
Full-Duplex, RS-485/RS-422 Transceivers
Data Sheet
ADM3483/ADM3485/ADM3488/ADM3490/ADM3491
Rev. E
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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
Telecom
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 com-
munication, while the ADM3483/ADM3485 are designed for
half-duplex communication.
FUNCTIONAL BLOCK DIAGRAMS
R
D
RO
CC
RE
DI
DE
ADM3483/
ADM3485
A
GND
B
05524-027
Figure 1.
R
D
RO
DI
ADM3488/
ADM3490
A
B
Z
Y
05524-026
CC
GND
Figure 2.
R
D
RO
RE
DI
DE
ADM3491
A
B
Z
Y
05524-025
Figure 3.
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
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.
