The addition of the XRT94L33 to Exar's pioneering SONET/SDH aggregation device family offers customers a new level of product support for their broadband applications. Capable of aggregating 3 DS3/E3/STS-1 into OC-3/STM-1, the device provides a vital link in Exar's product portfolio spanning T/E to SONET. The XRT94L33 supports Packet Over SONET (POS) and Asynchronous Transfer Mode (ATM) over SONET.
The process of mapping and subsequent de-mapping of individual DS3 or E3 signals into SONET's Synchronous Payload Envelope (SPE) can introduce excessive jitter and timing irregularities. Exar's solution uses only one highly integrated programmable PLL so each channel can support multi-rate (DS3, E3 or STS-1) operations. Here jitter/timing irregularities are removed, and then desynchronized to provide a smooth GR-253-CORE specification-compliant clock signal. Once this operation is complete the signal is suitable for retransmission and returned to the data stream. Examples of jitter sources include mapping jitter, caused by bit justification, or stuffing, to match the asynchronous bit rate to a synchronous transport signal; and pointer jitter, the outcome of frequency mismatches between two networks that offset the payload and cause pointer movement.
The XRT94L33 has an integrated clock and data recovery plus a serializer/ deserializer running at 155.52 MHz in order to support STS-3/STM-1 rate data allowing it to interface to an optical module. The chip offers three mappers for performing STS-1/VC-3 to STS-1/DS3/E3 mapping functions -- one for each STS-1/DS3/E3 framer.
Mapping and demapping in the XRT94L33 can occur in one of three modes. The first mode allows clear channel DS3, E3 or STS-1 to be directly mapped/ demapped to an STS-3 stream. This mode allows direct seamless connection to an EXAR LIU such as the XRT73L03 for termination on the DS3/E3/STS-1 side. The other two modes allow ATM cells or POS packets to be mapped onto the STS-3 directly. These modes provide termination either through a UTOPIA level II bus for ATM or a POS-PHY bus for POS.
Other features of this product include an on-chip clock synthesizer that generates 155.52 and 77.76 MHz clocks from a single 12.96, 19.44 or 77.76 MHz master clock providing development flexibility, reduced cost and ease of design. The device supports 1:1 and 1+1 Automatic Protection Switching (APS) through the K1 and K2 bytes allowing the device to be switched from primary to backup at the frame boundary. Level 2 performance monitoring capability is included allowing the analysis of overhead and payload envelope information with minimal data path delay.
Compliant to industry standards, the XRT94L33 supports Bellcore GR-253 by mapping and demapping asynchronous DS3 data into a STS-1 signal. In addition, it provides SDH TUG-3/VC-3 mapping or DS3/E3 in conformance with the ITU-T G. 707. Also, the XRT94L33 supports the ITU-T G.751, G.755, ETSI TBR24, GR253-CORE, GR-499-CORE and ANSI T1.105.03b jitter specifications.
- Provides STS-1 (EC1) Mapping/Demapping for up to 3 STS-1s
- Full APS Support for Full Redundancy Applications
- UTOPIA Level 2 Interface for ATM or Level 2P for Packets
- Complete Transport/Section Overhead Processing and Generation per Telcordia and ITU Standards
- Loopback Support for Both SONET/SDH as well as E3/DS3/STS-1
- Pb-Free, RoHS Compliant Versions Offered
- XRT94L33 3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
- XRT94L33 3-CHANNEL DS3 E3/STS-1 TO STS 3/STM-1 MAPPER – SDH REGISTERS
- XRT94L33 3-CHANNEL DS3 E3/STS-1 TO STS 3/STM-1 MAPPER – HARDWARE MANUALS
- XRT94L33 3-CHANNEL DS3 E3/STS-1 TO STS 3/STM-1 MAPPER – SONET REGISTERS
- XRT94L33 3-CHANNEL DS3 E3/STS-1 TO STS 3/STM-1 MAPPER – ATM REGISTERS
- SONET/SDH Multiplexers
- Digital Cross Connects
- Edge Switches
- Add/Drop Multiplexers
Parts & Purchasing
|Part Number||Pkg Code||RoHS||Min Temp||Max Temp||Status||Buy Now||Order Samples|
Active - the part is released for sale, standard product.
EOL (End of Life) - the part is no longer being manufactured, there may or may not be inventory still in stock.
CF (Contact Factory) - the part is still active but customers should check with the factory for availability. Longer lead-times may apply.
PRE (Pre-introduction) - the part has not been introduced or the part number is an early version available for sample only.
OBS (Obsolete) - the part is no longer being manufactured and may not be ordered.
NRND (Not Recommended for New Designs) - the part is not recommended for new designs.
Frequently Asked Questions
In this example, we looked for XRA1201. Click on part number header or on the link at the bottom of the result. This brings you to the product page. For example:
Click on Parts & Purchasing, highlighted with the blue arrow above. The screen changes to:
Notice the status column and the “Show obsolete parts” link. A legend tells you the definition of the different statuses. Click on the “Show obsolete parts” link to see EOL or OBS part numbers along with the Active part numbers, the legend still present:
Another method to find out if a part is OBS or EOL is to click on SUPPORT at the top:
And then Product Change Notifications:
Type the part into the search, and click on one of the part numbers from the drop down menu. Then you can look for the Product Discontinuation Notice, which generally is at the top of the list, for example:
If you see this, it tells you that this particular orderable part has been discontinued and when the last order date is, or was. If you click on the file, then you can view the notice we sent about this if you purchased the part in the recent past. It may also advise of a replacement part. When an orderable part first becomes discontinued, Product Discontinuation Notices are sent are sent to those who have purchased the parts in the recent past, if purchased directly, with a dated opportunity to place a last order.