3.3 V Slew Rate Limited,
Half Duplex RS-485/RS-422 Transceiver
ADM3493
Rev. 0
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FEATURES
Operates with 3.3 V supply
Interoperable with 5 V logic
EIA RS-422 and RS-485 compliant over full CM range
Data rate: 250 kbps
Half duplex transceiver
Reduced slew rates for low EMI
2 nA supply current in shutdown mode
Up to 256 transceivers on a bus
7 V to +12 V bus common-mode range
Specified over 40°C to +85°C temperature range
8 ns skew
Available in 8-lead SOIC
APPLICATIONS
Low power RS-485 applications
EMI sensitive systems
DTE-DCE interfaces
Industrial control
Packet switching
Local area networks
Level translators
FUNCTIONAL BLOCK DIAGRAM
R
D
RO
VCC
RE
DI
DE
ADM3493
A
GND
B
05
71
5-
00
1
Figure 1.
GENERAL DESCRIPTION
The ADM3493 is a low power, differential line transceiver
designed to operate using a single 3.3 V power supply. Low
power consumption, coupled with a shutdown mode, makes it
ideal for power-sensitive applications. The ADM3493 is suitable
for communication on multipoint bus transmission lines.
The device contains one driver and one receiver. Designed for
half-duplex communication, the ADM3493 features a slew rate
limited driver that minimizes EMI and reduces reflections
caused by improperly terminated cables, allowing error-free
data transmission at data rates up to 250 kbps.
The receiver input impedance is 96 kΩ, allowing up to 256
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 in the internal driver circuitry during fault
conditions then the thermal shutdown circuit forces the driver
output into a high impedance state. The receiver contains a fail-
safe feature that results in a logic high output state, if the inputs
are unconnected (floating).
The ADM3493 is fully specified over the commercial and
industrial temperature ranges and is available in an 8-lead SOIC.