ISL4489E Datasheet, PDF (1/12 Pages) Intersil Corporation – Low Power, High Speed and Slew Rate Limited, Full Duplex, RS-485/RS-422 Transceivers

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Data Sheet
ISL4489E, ISL4491E
October 27, 2004
FN6074.2
±15kV ESD Protected, 1/8 Unit Load, 5V,
Low Power, High Speed and Slew Rate
Limited, Full Duplex, RS-485/RS-422
Transceivers
The ISL4489E, ISL4491E are ESD protected, “fractional”
unit load, BiCMOS, 5V powered, single transceivers that
meet both the RS-485 and RS-422 standards for balanced
communication. Each driver output and receiver input is
protected against ±15kV ESD strikes, without latch-up.
Unlike competitive versions, these Intersil devices are
specified for 10% tolerance supplies (4.5V to 5.5V).
Rx inputs and Tx outputs present a “1/8 unit load” to the
RS-485 bus, which allows a total of 256 transmitters and
receivers on the network for large node count systems.
These devices are configured for full duplex (separate Rx
input and Tx output pins) applications, so they are ideal for
RS-422 networks requiring high ESD tolerance on the bus
pins.
The ISL4489E utilizes a slew rate limited driver which
reduces EMI, and minimizes reflections from improperly
terminated transmission lines, or unterminated stubs in
multidrop and multipoint applications.
Data rates up to 15Mbps are achievable by using the
ISL4491E, which features higher slew rates.
Receiver (Rx) inputs feature a “fail-safe if open” design,
which ensures a logic high Rx output if Rx inputs are floating.
Driver (Tx) outputs are short circuit protected, even for
voltages exceeding the power supply voltage. Additionally,
on-chip thermal shutdown circuitry disables the Tx outputs to
prevent damage if power dissipation becomes excessive.
Features
• Pb-free Available as an Option (RoHS Compliant)
(See Ordering Info)
• RS-485 I/O Pin ESD Protection . . . . . . . . . . . . . ±15kV HBM
- Class 3 ESD Level on all Other Pins . . . . . . >7kV HBM
• 1/8 Unit Load Allows up to 256 Devices on the Bus
• High Data Rates (ISL4491E) . . . . . . . . . . . up to 15Mbps
• Slew Rate Limited Version for Error Free Data
Transmission (ISL4489E)
• Very Low Quiescent Current:
- 140µA (ISL4489E)
- 370µA (ISL4491E)
• -7V to +12V Common Mode Input Voltage Range
• Three-State Rx and Tx Outputs
• Full Duplex Pinout
• Operates from a Single +5V Supply (10% Tolerance)
• Current Limiting and Thermal Shutdown for driver
Overload Protection
Applications
• Factory Automation
• Security Networks
• Building Environmental Control Systems
• Industrial/Process Control Networks
• Level Translators (e.g., RS-232 to RS-422)
• RS-232 “Extension Cords”
PART HALF/FULL
NUMBER DUPLEX
ISL4489E
Full
ISL4491E
Full
HIGH ESD?
Yes
Yes
TABLE 1. SUMMARY OF FEATURES
NO. OF DEVICES DATA RATE SLEW-RATE
RECEIVER/
QUIESCENT PIN
ALLOWED ON BUS (Mbps)
LIMITED? DRIVER ENABLE? I_CC (µA) COUNT
256
0.25
Yes
Yes
140
14
256
15
No
Yes
370
14
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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