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Texas Instruments Announces Industrys First RS-485 Differential Transceivers with Integrated Transient Voltage Protection

DALLAS (Dec. 2, 1996) The industrys first 176 standard footprint RS-485 differential transceivers to provide integrated transient voltage protection up to 400W peak (typical) are now available from Texas Instruments (TI). These devices are well-suited for high electrical noise applications such as industrial control, automated test equipment, alarm systems and point-of-sale equipment. According to industry analyst firm, Dataquest, TI is the leader in the interface product segment with a 28.2% market share in 1995.

The transceivers, designated the SN65LBC184 and SN75LBC184, provide protection from large over-voltage transients on the bus pins, and are designed to handle secondary pulse effects of a lightning strike without permanent damage. The SN65LBC184 and SN75LBC184 also offer slew rate controlled driver outputs to minimize the most frequent application problems of the RS-485 buses, including the use of extended stub lengths from the bus and unterminated busses. The SN65LBC184 and SN75LBC184 give designers over-voltage protection without the use of external discrete clamping diodes or costly multi-chip modules. The SN65LBC184 is characterized from -40 to 85 degrees Celsius and the SN75LBC184 from 0 to 70 degrees Celsius.

Features/Benefits

Integrated transient protection	Protects circuit from high-power noise transients, which reduces system down-time. Reduces lifetime costs and board-space requirements.
Controlled driver slew rates	Provides significantly improved data transmission over longer, unterminated cable runs and longer stub lengths from the main backbone cable.
High data rate with low	Transmits data at 250 Kbits per second electromagnetic interference (EMI) over unshielded twisted-pair cables or other balanced copper transmission media.
Half-unit load	Allows up to 64 similar devices to be connected on the bus.
Extensive features (open-circuit power up/down glitch protection and hysterisis.)	Enhances system performance and fail safe, thermal shutdown, improves reliability.
Compatibility	Meets or exceeds Electronic Industry Association (EIA) RS-485 and International Standards Organization (ISO) 8482:1993(87) (E) standards;to be a drop-in replacement of current 176 designs.

End Equipment Applications

Applications for the SN65LBC184 and SN75LBC184 include:

• Industrial control
  • Programmable logic controllers (PLCs)
  • Industrial PCs
  • Single-board computers
  • Industrial local-area networks (LAN)
  • Automated test equipment
  • Alarm systems
• Telecom
  • Data terminal equipment (DTE) (PCs, data terminals)
  • Data communications equipment (DCE) (modems, printers)
• Point-of-sale terminals
  • Credit reading machines
  • Cash registers

Pricing, Packaging and Availability

The SN65LBC184 and SN75LBC184 are now available from Texas Instruments and its authorized distributors. The devices are in an 8-pin dual in-line package (DIP) or small-outline integrated circuit (SOIC). The SN65LBC184 is priced at $2.72 and the SN75LBC184 is priced at $2.44, both in quantities of 1,000.