ISL31480E_10 Datasheet, PDF (1/24 Pages) Intersil Corporation – Fault Protected, Extended CMR, RS-485/RS-422 Transceivers with Cable Invert

Fault Protected, Extended CMR, RS-485/RS-422
Transceivers with Cable Invert
ISL31480E, ISL31483E, ISL31485E, ISL31486E
The ISL3148xE are fault protected, 5V powered
differential transceivers that exceed the RS-485 and
RS-422 standards for balanced communication. The
RS-485 transceiver pins (driver outputs and receiver
inputs) are protected against faults up to ±60V.
Additionally, the extended common mode range allows
these transceivers to operate in environments with
common mode voltages up to ±25V (>2X the RS-485
requirement), making this RS-485 family one of the
most robust on the market.
Transmitters deliver an exceptional 2.5V (typical)
differential output voltage into the RS-485 specified 54Ω
load. This yields better noise immunity than standard
RS-485 ICs, or allows up to six 120Ω terminations in star
network topologies.
Receiver (Rx) inputs feature a “Full Fail-Safe” design,
which ensures a logic high Rx output if Rx inputs are
floating, shorted, or on a terminated but undriven (idle)
bus.
The ISL31483E, ISL31485E and ISL31486E include cable
invert functions that reverse the polarity of the Rx and/or
Tx bus pins in case the cable is misconnected. Unlike
competing devices, Rx full fail-safe operation is
maintained even when the Rx input polarity is switched.
The ISL31480E and ISL31486E feature a logic supply
(V_L) pin that sets the V_OH of the Rx outputs, and the
switching points of the logic input pins, to be compatible
with a lower supply voltage (down to 1.8V) in mixed
voltage systems. See Table 1 on page 2 for key features
and configurations by device number.
Features
• Fault Protected RS-485 Bus Pins. . . . . . up to ±60V
• Extended Common Mode Range . . . . . . . . . . ±25V
More Than Twice the Range Required for RS-485
• Cable Invert Pins (Except ISL31480)
Corrects for Reversed Cable Connections While
Maintaining Rx Full Fail-safe Functionality
• Logic Supply (V_L) Pin (ISL31480E, ISL31486E)
Simplifies Interface to Lower Voltage Logic Devices
• Full Fail-safe (Open, Short, Terminated) RS-485
Receivers
• 1/4 Unit Load (UL) for up to 128 Devices on the Bus
• High Rx I_OL for Opto-Couplers in Isolated Designs
• Hot Plug Circuitry - Tx and Rx Outputs Remain
Three-State During Power-up/Power-down
• Slew Rate Limited RS-485 Data Rate . . . . . . 1Mbps
• Low Quiescent Supply Current . . . . . . . . . . . 2.3mA
Ultra Low Shutdown Supply Current . . . . . . . . 10µA
Applications*(see page 19)
• Utility Meters/Automated Meter Reading Systems
• High Node Count Systems
• PROFIBUS® and Field Bus Networks, and Factory
Automation
• Security Camera Networks
• Building Lighting and Environmental Control Systems
• Industrial/Process Control Networks
Exceptional Rx Operates at
1Mbps Even With ±25V
Common Mode Voltage
30
B
25
A
VID = ±1V
20
15
10
5
RO
0
-5
TIME (400ns/DIV)
Transceivers Deliver Superior
Common Mode Range vs.
Standard RS-485 Devices
25
12
0
-7
-12
-20
-25
STANDARD RS-485 CLOSEST
TRANSCEIVER COMPETITOR
ISL3148XE
June 25, 2010
FN7638.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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