ISL81486
5V, Half Duplex, 30Mbps, RS-485/RS-422 Transceiver

Key Features

• Specified for 10% Tolerance Supplies
• High Data Rates
  ISL4486 up to 40Mbps
  ISL81486 up to 30Mbps
  
• Large Differential Output Voltage 3V into 54Ω
• Low Bit-to-Bit (Part-to-Part) Skew for Parallel Applications
• 0.6 Unit Load Allows up to 50 Devices on the Bus
• ISL81486 is a Drop-In Replacement for the ADM1486
• Low Quiescent Current 800µA
• -7V to +12V Common Mode Input Voltage Range
• Three State Rx and Tx Outputs
• 14ns (Max) Propagation Delays, 2ns (Max) Skew
• Operates from a Single +5V Supply (10% Tolerance)
• Current Limiting and Thermal Shutdown for driver Overload Protection

Description

The Intersil ISL4486 and ISL81486 are BiCMOS, 5V powered, single transceivers that meet both the RS-485 and RS-422 standards for balanced communication, and feature the larger output voltage and higher data rate - up to 40Mbps - required by high speed PROFIBUS applications.

Unlike competitive products, these Intersil devices are specified for 10% tolerance supplies (4.5V to 5.5V) and deliver at least a 2.3V differential output voltage over this supply range. At the 5% tolerance specified by many competitors, the ISL4486 delivers an unsurpassed 2.5V differential signal into a 54Ω total load. This translates into longer reach, or better data integrity, at the exceptional 40Mbps data rate.

SCSI applications benefit from the ISL4486's low receiver and transmitter part-to-part skews, which make it perfect for high speed parallel applications where large numbers of bits must be simultaneously captured. The low bit-to-bit skew eases the timing constraints on the data latching signal.

These devices present a "0.6 unit load" to the RS-485 bus, which allows up to 50 transceivers on the network. 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.

Applications

• SCSI "Fast 40" Drivers and Receivers
• PROFIBUS DP and FMS Networks
• Factory Automation
• Field Bus Networks
• Security Networks
• Building Environmental Control Systems
• Industrial/Process Control Networks