ISL31470E_10 Datasheet, PDF (1/21 Pages) Intersil Corporation – Fault Protected, Extended Common Mode Range, RS-485/RS-422 Transceivers

Fault Protected, Extended Common Mode Range,
RS-485/RS-422 Transceivers
ISL31470E, ISL31472E, ISL31475E, ISL31478E
The ISL31470E, ISL31472E, ISL31475E, ISL31478E are
fault protected, extended common mode range
differential transceivers that exceed the RS-485 and
RS-422 standards for balanced communication. The
RS-485 bus pins (driver outputs and receiver inputs)
are protected against overvoltages up to ±60V.
Additionally, these transceivers operate in environments
with common mode voltages up to ±15V (exceeds the
RS-485 requirement), making this RS-485 family one
of the more 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
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. Rx outputs feature high drive levels - typically
15mA @ V_OL = 1V (to ease the design of opto-coupled
isolated interfaces).
Half duplex (Rx inputs and Tx outputs multiplexed
together) and full duplex pinouts are available. See Table
1 on page 2 for key features and configurations by device
number.
For an RS-485 family with a ±25V extended common
mode range, please see the ISL31490E and ISL31480E
data sheets.
Features
• Fault Protected RS-485 Bus Pins. . . . . . .up to ±60V
• Extended Common Mode Range . . . . . . . . . . . ±15V
Larger Than Required for RS-485
• 1/4 Unit Load for up to 128 Devices on the Bus
• High Transient Over Voltage Tolerance . . . . . . ±80V
• Full Fail-safe (Open, Short, Terminated) RS-485
Receivers
• 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
• Choice of RS-485 Data Rates . . . .250kbps to 15Mbps
• Low Quiescent Supply Current . . . . . . . . . . 2.3mA
Ultra Low Shutdown Supply Current . . . . . . . 10μA
• Pb-Free (RoHS Compliant)
Applications
• 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
>15Mbps Even with ±15V
Common Mode Voltage
20
B
15
A
VID = ±1V
10
5
RO
0
-5
TIME (20ns/ DIV)
Transceivers Deliver Superior
Common Mode Range vs
Standard RS-485 Devices
15
12
0
-7
-15
STANDARD RS-485
TRANSCEIVER
ISL3147xE
June 17, 2010
FN7639.0
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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