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Intersil's Latest 3.3-V RS-485/422 Transceivers Bring Speed, Data Integrity and Cost Savings to Industrial Serial Data Communications
-- New full-duplex 3.3-V transceivers operate over a +/-10% voltage range to reduce supply cost
MILPITAS, CA, October 20, 2003 Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high performance analog solutions, today announced two new RS-485/422 serial data transceivers, the ISL83488 and ISL83490. Both ICs are full-duplex transceivers that operate from a nominal 3.3-V supply over a wide +/-10% voltage range of +3 to +3.6 V, which relaxes supply requirements and reduces costs. These new ICs satisfy both low- and high-speed (250 kbps and 10 Mbps) serial communications needs as used in, but not limited to, factory automation, security networks and building environmental control.
The ISL83488 and ISL83490 are both configured for full-duplex operation with separate Rx input and Tx output pins. These devices are well suited for RS-422 applications because they dont typically require Tx and Rx enable functions and both driver and receiver are independently accessible. By eliminating the enable functions, full duplex functionality is realized in a small 8-lead package. These 3.3-V devices can be driven with 5-V logic levels in mixed voltage systems. Rx inputs feature a fail-safe-if-open design, which ensures a logic high Rx output if Rx inputs are floating. This prevents the Rx output from chattering, and accidentally generating interrupts, if the receiver becomes disconnected from the bus.
Driver outputs are short circuit protected. Additionally, on-chip thermal shutdown circuitry disables the Tx outputs to prevent damage if power dissipation becomes excessive. Each device supports a combination of up to 32 drivers and receivers on a single bus enabling large 4-wire full duplex systems.
The ISL83488 is slew-rate limited for error free data transmission in applications where the data rate is less than 250 kbps, typically used for long runs. Slew-rate limiting reduces EMI and minimizes reflections from improperly terminated transmission lines, or unterminated stubs in multi-drop and multipoint applications.
The ISL83490 can operate up to 10 Mbps for high-speed applications. These transceivers are built using the Intersil BiCMOS process and meet both the RS-485 and RS-422 standards for balanced (differential) communication. Balanced data-transmission schemes offer robust noise immunity for data communications over long distances.
The typical use for RS-485 is a single PC connected to several addressable devices that share the same cable. RS-422 is similar to RS-485 except that only one driver and up to ten receivers are allowed on the bus. The single driver limitation requires two twisted pairs for bi-directional communications.
ISL83488 and ISL83490 Technical Details
- Pin-for-pin replacements for competing products of similar nomenclature
- +3.3 V supply, +/-10% voltage tolerance, +3.0 to +3.6 V range
- Full-duplex bidirectional operation, differential signaling
- Driver inputs accept 5-V logic levels (i.e., can exceed the supply voltage)
- RS-485 and RS-422 compliant
- Ideal for RS-422 applications that typically dont require Tx and Rx enable functions
- ISL83488 slew-rate limited, less than 250 kbps data rate, low EMI
- ISL83490 10 Mbps data rate
- -7 to +12 V common-mode input voltage range for reliable operation over long, noisy runs
- Single-unit RS-485 loading allows 32 units on the bus
- On-chip thermal shutdown
- Driver outputs short-circuit protected
- 8-lead PDIP and SOIC packages
The ISL83488 and ISL83490 are available now. Suggested resale pricing for 100- to 999-unit quantities is $1.20 each for the ISL83488IB (SOIC package), ISL83488IP (PDIP package), ISL83490IB (SOIC package) and ISL83490IP (PDIP package). SOIC packages are available on tape and reel. Visit this Intersil Web site for cross-reference and other information: http://www.intersil.com/design/interface/rs-485.asp About Intersil
Intersil Corporation is a leader in the design and manufacture of high performance analog semiconductors. The company’s products address three of the industry’s fastest growing markets - flat panel displays, optical storage (CD and DVD recordable) and power management. Intersil products include power management devices for battery management, hot-swap and hot-plug controllers, linear regulators, supervisory ICs, switching DC-DC regulators and power MOSFET drivers; optical storage laser diode drivers; DSL line drivers; video and high performance operational amplifiers; data converters; interface ICs; analog switches and multiplexers; crosspoint switches; voice-over-IP devices; and ICs for military, space and rad-hard applications. For more information about Intersil or to find out how to become a member of our winning team, visit the company’s web site and career page at: www.intersil.com.
This release may include "forward looking statements" that are subject to risks and uncertainties. For information identifying economic, political, climatic, currency, regulatory, technological, competitive and some other important factors that could cause actual results to differ materially from those anticipated in the forward looking statements, see Intersil’s Safe Harbor Forward Looking Statement disclaimer found at http://www.intersil.com/legal.asp, as well as Intersil’s SEC filings as updated from time to time, found at http://www.sec.gov. All other trademarks mentioned are the property of their respective owners.
