Multi-Channel, Multi-Function Device Aggregates 3 DS3/E3/STS-1 into OC3/STM-1
OBS (Obsolete)
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Information Multi-Channel, Multi-Function Device Aggregates 3 DS3/E3/STS-1 into OC3/STM-1
Package PBGA-504
Bus I/F 8-Bit, 77.76MHz
Line Interface 1xSTS-3 1xSTM-1 3xDS3/E3/STS-1
Pwr Sup 3.3V
System Bus I/F Utopia/POS PHY
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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.

Product Highlights

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.

Standards Compliance

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

  • SONET/SDH Multiplexers
  • Digital Cross Connects
  • Concentrators
  • Edge Switches
  • Add/Drop Multiplexers

Documentation & Design Tools

Type Title Version Date File Size
Schematics & Design Files Schematic 1.0.0 January 2004 99.2 KB
Schematics & Design Files Schematic 1.0.0 January 2004 301 KB
Simulation Models
Package Type Vcc Temp Mode Version File
TBGA 3.3V Industrial 4
Package Type File
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Quality & RoHS

Part Number RoHS | Exempt RoHS Halogen Free REACH TSCA MSL Rating / Peak Reflow Package
XRT94L33IB N N Y Y Y L4 / 245ᵒC TBGA504

Click on the links above to download the Certificate of Non-Use of Hazardous Substances.

Additional Quality Documentation may be available, please Contact Support.

Parts & Purchasing

Part Number Pkg Code Min Temp Max Temp Status Suggested Replacement PDN
XRT94L33IB TBGA504 -40 85 OBS
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Part Status Legend
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.


Pkg Code Details Quantities Dimensions PDF
  • JEDEC Reference: n/a
  • MSL Pb-Free: L4 @ 245ºC
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 10.2ºC/W
  • Bulk Pack Style: Tray
  • Quantity per Bulk Pack: n/a
  • Quantity per Reel: n/a
  • Quantity per Tube: n/a
  • Quantity per Tray: 24
  • Reel Size (Dia. x Width x Pitch): n/a
  • Tape & Reel Unit Orientation: n/a
  • Dimensions: mm
  • Length: 35
  • Width: 35
  • Thickness: 1.7
  • Lead Pitch: 1.27


Distribution Date Description File
06/09/2021 Product Discontinuation Notice
07/26/2016 Product discontinuation notification. Discontinued.
12/11/2008 Ordering part number Exar is redefining the “-F” and – “L” portion of part number nomenclature.

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