Datasheet

16 Mbps, ESD Protected,
Full-Duplex RS-485 Transceivers
Data Sheet
ADM1490E/ADM1491E
Rev. D
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FEATURES
RS-485/RS-422 full-duplex transceiver for high speed
motor control applications
16 Mbps data rate
±8 kV ESD protection on RS-485 input/output pins
Complies with ANSI/TIA/EIA-485-A-1998
Open circuit fail-safe
Suitable for 5 V power supply applications
32 nodes on the bus (1 unit load)
Thermal shutdown protection
Operating temperature range: −40°C to +85°C
ADM1490E packages
Narrow body, 8-lead SOIC
8-lead MSOP
ADM1491E packages
Narrow-body, 14-lead SOIC
10-lead MSOP
APPLICATIONS
RS-485/RS-422 interfaces
Industrial field networks
High data rate motor control
Multipoint data transmission systems
Single-ended-to-differential signal conversion
FUNCTIONAL BLOCK DIAGRAMS
ADM1490E
RO
DI
A
B
Z
Y
V
CC
GND
R
D
07430-001
Figure 1.
ADM1491E
RO
RE
DE
DI
A
B
Z
Y
GND
R
D
V
CC
07430-002
Figure 2.
GENERAL DESCRIPTION
The ADM1490E/ADM1491E are RS-485/RS-422 transceivers
with ±8 kV ESD protection and are suitable for high speed, full-
duplex communication on multipoint transmission lines. In
particular, the ADM1490E/ADM1491E are designed for use in
motor control applications requiring communications at data
rates up to 16 Mbps.
The ADM1490E/ADM1491E are designed for balanced trans-
mission lines and comply with TIA/EIA-485-A-98. The devices
each have a 12 kΩ receiver input impedance for unit load RS-485
operation, allowing up to 32 nodes on the bus.
The differential transmitter outputs and receiver inputs feature
electrostatic discharge circuitry that provides protection to ±8 kV
using the human body model (HBM).
The ADM1490E/ADM1491E operate from a single 5 V power
supply. Excessive power dissipation caused by bus contention
or output shorting is prevented by short-circuit protection and
thermal circuitry. Short-circuit protection circuits limit the
maximum output current to ±250 mA during fault conditions.
A thermal shutdown circuit senses if the die temperature rises
above 150°C and forces the driver outputs into a high impedance
state under this condition.
The receiver of the ADM1490E/ADM1491E contains a fail-safe
feature that results in a logic high output state if the inputs are
unconnected (floating).
The ADM1490E/ADM1491E feature extremely fast and closely
matched switching times. Minimal driver propagation delays
permit transmission at data rates up to 16 Mbps, and low skew
minimizes EMI interference.
The ADM1490E/ADM1491E are fully specified over the
commercial and industrial temperature ranges. The ADM1490E
is available in two packages: a narrow body, 8-lead SOIC and an
8-lead MSOP. The ADM1491E is also available in two packages:
a narrow body, 14-lead SOIC and a 10-lead MSOP.