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Exar, Infineon framer designs take different directions

Posted: 18 Jan 2002 ?? ?Print Version ?Bookmark and Share

Keywords:exar? infineon? framer? xrt84l38? falc56?

Makers of communications chips are addressing integration and channel capacity issues from opposite directions, but they expect to deliver similar benefits in the near term and might find themselves competing head-to-head before long.

Responding to customer demands for greater channel capacities, Exar Corp. has launched an octal framer, for use where four-channel devices had prevailed. Infineon Technologies Corp., on the other hand, which had previously integrated a single-channel framer with an LIU, has repackaged that combination into a BGA. Both companies' products target T1/E1/J1 applications.

Increasing a chip's channel capacity effectively reduces the cost per channel while also lowering power consumption and board-space requirements. Integrating two functions in a single chip similarly saves money, space and design time. The logical design direction leads to multichannel framer devices, such as Exar's, that integrate LIUs, as does Infineon's part, in smaller packages with lower power consumption.

Exar's XRT84L38 is designed for use in high-density T1/E1/J1 interfaces for multiplexers, switches, routers and modems. Hugh Wright, director of marketing, said the device supports high-speed interfacing, offers fast access to path maintenance data and can be connected seamlessly to the company's long-haul, short-haul LIUs.

Wright added that Exar plans to introduce a series of multichannel ICs that combine a framer with an LIU. "Most framer and LIU combinations are no more than four channels, compared with the eight we can offer with this new device," he said.

The new octal supports direct memory access for path maintenance data supplied through the LAP-D channel. The feature enables the framer to move data quickly to and from the system memory by handling the data in 96-byte blocks, rather than one byte at a time.

The device supports a variety of backplane standards, with clock rates of up to 16.384MHz, Wright said. "This allows the design of a system to process T1/E1 data rapidly-up to a data rate of 8.192Mbps [4x E1 rates], while minimizing traces between the framer and system-side circuitry," He added that the device supports microprocessor speeds of up to 40MHz, which allows real-time processing of interrupts, alarms and signaling information.

The chip contains eight integrated T1/E1/J1 framers, which provide framing, error detection and performance monitoring in accordance with ANSI/ITU-T specifications.

Each framer has its own framing synchronizer and transmit-receive slip buffers, and can be independently enabled or disabled. A transmit and overhead data input port in each framer provides data link terminal equipment with direct access to the outbound T1/E1/J1 frames.

The receive overhead output data port gives the terminal equipment access to the data link bits of the inbound frames. Diagnostic and test functions incorporated into the chip include loopbacks, boundary scan, pseudorandom bit-sequence test pattern generation, performance monitoring and a bit-error-rate counter.

The XRT84L38 comes in a 388-pin BGA and operates at 3.3V, with 5V-tolerant I/Os, over the industrial temperature range. It is priced at $69.84 in 1,000-piece quantities. Samples are expected during the first quarter.

Infineon's FALC56 is the latest version of its single-channel framer and line-interface unit component for T1/E1/J1 for use in carrier line cards and other telecommunications equipment. It is housed in a LFBGA 81 package that measures 10-by-10mm and has a 1mm ball pitch.

An earlier single-channel device (PEB2256H) is still available in an 80-pin QFP, and Infineon offers a quad framer, LIU and signaling controller (QuadFALC PEB2254) for multichannel applications.

"Designers of TE carrier line cards have four main criteria when selecting components-time-to-market, small size, low power and compliance with recognized standards," said Christian Wolff, vice president of Infineon's Communications group and general manager of its access business unit.

He said that Infineon's new single-channel device meets T1/E1/J1 short- and long-haul requirements and that it features a typical power dissipation <220mW. It can operate from any available clock source in the 1MHz to 20MHz range and is software-switchable between T1/J1 and E1 operation.

Consequently, the device can support applications that must meet all three worldwide Primary Rate standards with a minimum number of external components.

Three high-level data link control controllers integrated with the LIU and framer suit the device for use in wireless basestations, switches, routers and Internet access equipment. It also suits application that require compliance with v5.1 and v5.2 interface standards and support of Signaling System 7.

The FALC56 (PEB2256E) is sampling now and is priced at less than $12 in quantities of 100,000 or more.

John H. Day

EE Times

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