SOURCE: Intersil

February 19, 2007 06:00 ET

Intersil's RS-485/RS-422 Family of Transceivers Delivers the Highest Noise Immunity and ESD Protection in Small Packages

ISL315XE Family of 5V RS-485/RS-422 Transceivers Delivers IEC61000 ESD Protection and 60% Higher Output Voltage While Consuming 50-70% Less Board Space

MILPITAS, CA -- (MARKET WIRE) -- February 19, 2007 -- Intersil Corporation (NASDAQ: ISIL), a world leader in the design and manufacture of high-performance analog semiconductors, today introduced the ISL315XE family of 5V RS-485/RS-422 transceivers. This six-member family saves 50-70% of valuable board space with tiny 8- and 10-lead MSOP package options and delivers data transmission rates up to 20Mbps.

The ISL315XE family provides maximum reliability of exposed transmitter and receiver RS-485 bus pins with IEC61000 ESD (electrostatic discharge) protection that allows customers to develop the most rugged systems possible for harsh industrial environments. The family's higher output voltage (2.4V min.) is 60% larger than the 1.5V required by the RS-485 standard, providing the advantage of nearly 1V greater noise immunity and the ability to drive longer cable lengths, resulting in a more robust serial communication system.

"The unique combination of high ESD protection and increased output drive gives designers of high-performance industrial applications a new level of system reliability," said Randy Pitts, marketing manager of Intersil's Interface products group. "Combining the tiny MSOP package option will enable smaller PCB designs or additional features in the same area."

Reliable Performance and Protection

The ISL315XE family is made up of BiCMOS, IEC61000 ESD-protected, 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 +/-16.5kV ESD strikes without latch-up.

The ISL315XE transmitters all deliver exceptional differential output voltages (2.4V min), into the RS-485 required 54 Ohm load, for better noise immunity or to allow up to eight 120 Ohm terminations in "star" or other non-standard bus topologies. These transmitters deliver RS-485 compliant levels (1.5V) even with eight termination resistors. Unlike competing devices that require up to 15mA quiescent supply currents, the ISL315XE family requires only 800uA (maximum). Power consumption is further reduced via a low-power shutdown feature that reduces Icc to 70nA when the driver and receiver are both disabled.

These devices have very low bus currents, so they provide a true 1/8 unit load to the RS-485 bus. This allows up to 256 transceivers on the network without violating the RS-485 specification's 32-unit load maximum and without using repeaters.

Receiver (Rx) inputs feature a "full fail-safe" design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or on a terminated but undriven bus. Rx outputs feature high drive levels -- typically 28mA @ VOL = 1V -- to ease the design of optocoupled isolated interfaces.

The ISL3150E, ISL3152E, ISL3153E and ISL3155E utilize slew-rate-limited drivers which reduce EMI and minimize reflections from improperly terminated transmission lines, or unterminated stubs in multidrop and multipoint applications. The ISL3156 and ISL3158 are rated up to 20Mbps data rate for high-speed applications.

Hot plug circuitry ensures that the Tx and Rx outputs remain in a high impedance state until the power supply has stabilized. The Tx outputs have full short circuit protection.

The ISL3150E, ISL3153E, ISL3156E are configured for full duplex (e.g., RS-422) applications. The half duplex versions multiplex the Rx inputs and Tx outputs to allow transceivers with output disable functions in 8-lead packages.

ISL315XE Key Features

--  High driver VOD 2.4V (Min) @ RD = 54 Ohms for better noise
    immunity, or to drive up to 8 terminations
--  IEC61000 ESD protection on RS-485 I/O pins +/-16.5kV
    -- Class 3 ESD level on all other pins > 7kV HBM
--  Tiny MSOP packages save 50-70% board space
--  Full fail-safe (open, short, terminated and undriven) receivers
--  High Rx IOL to drive opto-couplers for isolated applications
--  Hot plug circuitry - Tx and Rx outputs remain three-state during
--  True 1/8 unit load allows up to 256 devices on the bus
--  Specified for single 5V, 10% tolerance, supplies
--  Data rates up to 20Mbps
--  Low quiescent supply current 600µA; ultra low shutdown supply
    current 70nA
--  -7V to +12V common mode input voltage range
Target Applications
--  Utility meters and automated meter reading systems
--  High node count systems and networks requiring more than two
    termination resistors
--  PROFIBUS® and field bus networks, and factory automation
--  Security camera networks
--  Building lighting and environmental control systems
--  Industrial/process control networks
About Intersil's Interface Portfolio

This new RS-485/RS-422 family 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-485/422 family of devices comes in 3.3V or 5V supply operation, supports full/half duplex modes, with many speed grades to choose from, and many are ESD protected to either 15kV HBM, or 15kV IEC61000. 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

Pricing and Availability

The ISL315XE 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 $1.26 in 1,000-unit quantities. More information on the ISL315XE family is available at

Note to editors: To view a high-resolution downloadable photo of the ISL315XE family, visit Intersil's photo room at:

About Intersil

Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products address some of the industry's fastest growing markets, such as flat panel displays, cell phones, other handheld systems, and notebooks. Intersil's product families address power management functions and analog signal processing functions. Intersil products include ICs for battery management, hot-swap and hot-plug controllers, linear regulators, power sequencers, supervisory ICs, bridge drivers, PWM controllers, 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 radiation-hardened 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

Contact Information

  • Media Contact
    Kim Fehrt
    Public Relations Manager
    Intersil Corporation
    (408) 546-3566
    Email Contact