High Speed, ESD-Protected, Half-/Full-Duplex
iCoupler Isolated RS-485 Transceiver
Isolated, RS-485/RS-422 transceiver, configurable as half- or
±8 kV ESD protection on RS-485 input/output pins
16 Mbps data rate
Complies with ANSI TIA/EIA RS-485-A-1998 and
ISO 8482: 1987(E)
Suitable for 5 V or 3.3 V operation (VDD1)
High common-mode transient immunity: >25 kV/μs
Receiver has open-circuit, fail-safe design
32 nodes on the bus
Thermal shutdown protection
Safety and regulatory approvals
UL recognition: 5000 V rms isolation voltage
for 1 minute, per UL 1577
VDE certificate of conformity
DIN V VDE V 0884-10 (VDE V 0884-10): 2006-12
Reinforced insulation, VIORM = 849 V peak
Operating temperature range: −40°C to +85°C
Wide body, 16-lead SOIC package
Isolated RS-485/RS-422 interfaces
Industrial field networks
Multipoint data transmission systems
FUNCTIONAL BLOCK DIAGRAM
The ADM2491E is an isolated data transceiver with ±8 kV ESD
protection and is suitable for high speed, half- or full-duplex
communication on multipoint transmission lines. For half-
duplex operation, the transmitter outputs and the receiver
inputs share the same transmission line. Transmitter output
Pin Y is linked externally to receiver input Pin A, and transmit-
ter output Pin Z is linked to receiver input Pin B.
The ADM2491E is designed for balanced transmission lines
and complies with ANSI TIA/EIA RS-485-A-1998 and ISO
8482: 1987(E). The device employs Analog Devices, Inc.,
iCoupler® technology to combine a 3-channel isolator, a three-
state differential line driver, and a differential input receiver into
a single package.
The differential transmitter outputs and receiver inputs feature
electrostatic discharge circuitry that provides protection to
±8 kV using the human body model (HBM). The logic side of
the device can be powered with either a 5 V or a 3.3 V supply,
whereas the bus side requires an isolated 5 V supply.
The device has current-limiting and thermal shutdown features
to protect against output short circuits and situations in which
bus contention could cause excessive power dissipation.
The ADM2491E is available in a wide body, 16-lead SOIC package
and operates over the −40°C to +85°C temperature range.
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 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.
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