Half-Duplex, i
Coupler®
Isolated RS-485 Transceiver
ADM2483
FUNCTIONAL BLOCK DIAGRAM
FEATURES
RS-485 transceiver with electrical data isolation
Complies with ANSI TIA/EIA RS-485-A and ISO 8482: 1987(E)
500 kbps data rate
V
V
DD2
DD1
ADM2483
DE
Slew rate-limited driver outputs
Low power operation: 2.5 mA max
TxD
Suitable for 5 V or 3 V operations (VDD1
High common-mode transient immunity: >25 kV/μs
True fail-safe receiver inputs
Chatter-free power-up/power-down protection
256 nodes on bus
)
PV
RxD
RE
A
B
Thermal shutdown protection
GND
GND
2
1
Safety and regulatory approvals
Figure 1.
UL recognition: 2500 Vrms for 1 minute per UL 1577
CSA Component Acceptance Notice #5A
VDE Certificate of Conformity
DIN EN 60747-5-2 (VDE 0884 Rev. 2): 2003-01
DIN EN 60950 (VDE 0805): 2001-12; EN 60950: 2000
VIORM = 560 V peak
Operating temperature range: −40°C to +85°C
APPLICATIONS
Low power RS-485/RS-422 networks
Isolated interfaces
Building control networks
Multipoint data transmission systems
and receiver differential inputs are connected internally to form
a differential I/O port. When the driver is disabled or when
VDD1 or VDD2 = 0 V, this imposes minimal loading on the bus.
An active-high receiver disable feature, which causes the receive
output to enter a high impedance state, is provided as well.
GENERAL DESCRIPTION
The ADM2483 differential bus transceiver is an integrated,
galvanically isolated component designed for bidirectional data
communication on balanced, multipoint bus transmission lines.
It complies with ANSI EIA/TIA-485-A and ISO 8482: 1987(E).
Using Analog Devices’ iCoupler technology, the ADM2483
combines a 3-channel isolator, a three-state differential line
driver, and a differential input receiver into a single package.
The logic side of the device is powered with either a 5 V or 3 V
supply, and the bus side uses a 5 V supply only.
The receiver inputs have a true fail-safe feature that ensures a
logic-high receiver output level when the inputs are open or
shorted. This guarantees that the receiver outputs are in a
known state before communication begins and at the point
when communication ends.
The ADM2483 is slew-limited to reduce reflections with
improperly terminated transmission lines. The controlled slew
rate limits the data rate to 500 kbps. The device’s input impedance
is 96 kΩ, allowing up to 256 transceivers on the bus. Its driver
has an active-high enable feature. The driver differential outputs
Current limiting and thermal shutdown features protect against
output short circuits and bus contention situations that might
cause excessive power dissipation. The part is fully specified
over the industrial temperature range and is available in a
16-lead, wide body SOIC package.
Rev. B
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