Intersil Introduces Robust RS-485 Transceivers in Tiny MSOP Package

ISL317XE Family of 3.3V RS-485/RS-422 Transceivers Delivers IEC61000 ESD Protection and 20Mbps Data Transmission Rate While Consuming 50-70% Less Board Space

Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high-performance analog semiconductors, today introduced the ISL317XE family of 3.3V RS-485/RS-422 transceivers. This versatile nine-member family saves 50-70% of valuable board space and delivers the industry’s only full-featured IEC61000 ESD-protected transceivers with 20Mbps data transmission rate.

The ISL317XE line provides maximum reliability of exposed transmitter and receiver pins with IEC61000 ESD (electrostatic discharge) protection that allows customers to develop the most rugged systems possible.

“IEC61000 ESD protection on the I/O pins and 7kV HBM on all other pins in Intersil’s ISL317XE family provides a high degree of reliability in both manufacturing and end consumer applications and eliminates the need for external protection circuitry,” said Randy Pitts, marketing manager of Intersil’s Interface products group.

The line’s enhanced features include full fail-safe design and hot plug capability, full/half duplex, and three data rate options. The family’s full fail-safe feature eliminates external components and ensures consistent performance when bus faults occur.

The new devices come in space-saving MSOP (mini small-outline package) sizes that allow designs to drop old 8- and 14-lead SOIC transceivers. The 8-lead MSOP package provides a 50 percent board space savings over 8-lead SOIC packages and Intersil’s 10-lead MSOP package saves 70 percent over old 14-lead SOIC package options.

“We believe the ongoing change from 5V to 3.3V supply voltages is permanent,” Pitts said. “Our board space advantage over our competitors will become more important as those changes continue throughout the industry.”

Applications include factory automation, security networks, building environmental control systems, industrial/process control systems and automated utility meter reading systems.

The ISL317XE family covers all features and configurations associated with the RS-485 protocol.
Data rate options are offered to match the application speed. For low-speed applications, the family offers slew-rate-limited versions at 250kbps: ISL3170E/71E/72E, and 500kbps: ISL3173E/74E/75E. The ISL3176E/77E/78E operates up to 20Mbps for high-speed applications.

Reliable Performance and Protection
The ISL317XE family’s hot plug circuitry ensures active data on the bus won’t be corrupted when the new device is connected to it. Slew-rate limited drivers reduce EMI (electromagnetic interference) and minimize reflections from improperly terminated transmission lines or unterminated stubs in multidrop and multipoint applications. Slew-rate limited versions also have receiver input filtering to reduce the impact of noise on slow input signals.

All devices present a light “one-eighth unit load” to the RS-485 bus, allowing up to 256 transceivers on the network. Tx outputs and Rx inputs maintain this load even when the voltages exceed the supply voltages by as much as -7V and +9V (i.e., from –7V to +12V).

Rx inputs feature a full fail-safe design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or terminated but undriven. The hot plug circuitry ensures that the Tx and Rx outputs remain tri-state during power up/power down. Driver outputs are short-circuit protected, even for voltages exceeding the power supply voltage. Also, on-chip thermal shutdown circuitry disables the Tx outputs to prevent damage if power dissipation becomes excessive.

The ISL3172E/75E/78E are half duplex configurations that multiplex the receiver (Rx) inputs and driver (Tx) outputs to allow transceivers with Rx and Tx disable functions in 8-lead packages. These parts come in a standard 8-lead SOIC as well as tiny 8-lead MSOP for space-constrained applications. The ISL83070E/73E/76E are full duplex configurations with Tx/Rx enable/disable functions. All three come in 14-lead SOIC and 10-lead MSOP packages. The ISL83071E/74E/77E are configured for full duplex without the enable function (RS-422) that allows them to fit into 8-lead SOIC/MSOP packages.

ISL317XE Key Features
•3.3V operation with 10 percent tolerance
•20Mbps data rate
•Slew rate limited
•Hot plug
•Full fail-safe
•IEC61000 ESD protection on the I/O pins
•Class 3 ESD protection (less than 7kV HBM) on all pins
•Tiny RoHS MSOP package option
•-7V to +12V common mode input and output voltage range
•Fractional unit load

Target Applications
•Factory automation
•Security networks
•Industrial/process control networks
•Building environmental control systems
•Automated utility meter reading systems

About Intersil’s Interface Portfolio
This new RS-485 is the latest enhancement to our current broad offering of interface products. Intersil offers a wide range of RS-232 and RS-485/422 transceivers. The RS-485 family of devices comes in 3.3V or 5V supply operation, supports full/half duplex modes, with many speed grades to chose from, and is protected to 15kV HBM ESD. The RS-232 family of devices operates off of 3.3V or 5V supplies and has a wide array of combinations for transmitter and receiver configurations. It is protected to IEC61000 ESD specifications. Recently, Intersil released a dual protocol family. These devices give the designer the flexibility to program the serial port to comply with either the RS-232 or RS-485 protocol. To learn more, visit Intersil’s Interface page at http://www.intersil.com/interface/.

Pricing and Availability
The ISL317XE family is available now in 8-lead MSOP packages, 8-lead SOIC packages, 10-lead MSOP packages and 14-lead SOIC packages with prices starting at $1.68 in 1,000-unit quantities.

More information on the ISL317XE family is available at http://www.intersil.com/products/partsearch.asp?txtprodnr=isl317.

To view a broad range of application block diagrams, visit Intersil’s Application Design Center at http://www.intersil.com/apps.

Note to editors: To view a high-resolution downloadable photo of the ISL317XE family, visit Intersil’s photo room at: http://www.intersil.com/pressroom/photoarchives.asp.