4-Channel DS3/E3/STS-1 Line Interface Unit


The XRT73LC04A, 4-Channel, DS3/E3/STS-1 Line Interface Unit is a low power CMOS version of the XRT73L04A and consists of four independent line transmitters and receivers integrated on a single chip designed for DS3, E3 or SONET STS-1 applications. Each channel of the XRT73LC04A can be configured to support the E3 (34.368 Mbps), DS3 (44.736 Mbps) or the SONET STS-1 (51.84 Mbps) rates. Each channel can be configured to operate in a mode/data rate that is independent of the other channels. In the transmit direction, each channel encodes input data to either B3ZS (DS3/STS-1) or HDB3 (E3) format and converts the data into the appropriate pulse shapes for transmission over coaxial cable via a 1:1 transformer.

In the receive direction, the XRT73LC04A performs equalization on incoming signals, performs Clock Recovery, decodes data from either B3ZS or HDB3 format, converts the receive data into TTL/CMOS format, checks for LOS or LOL conditions and detects and declares the occurrence of Line Code Violations.


  • Incorporates an improved Timing Recovery circuit and is pin and functional compatible to XRT73L04A
  • Meets E3/DS3/STS-1 Jitter Tolerance Requirements
  • Contains a 4-Wire Microprocessor Serial Interface
  • Full Loop-Back Capability
  • Transmit and Receive Power Down Modes
  • Full Redundancy Support
  • Uses Minimum External components
  • Single +3.3V Power Supply
  • Low Power CMOS design
  • 5V tolerant I/O
  • -40°C to +85°C Operating Temperature Range
  • Available in a Thermally Enhanced 144 pin TQFP package
  • Pb-Free, RoHS Compliant Versions Offered


  • Digital Cross Connect Systems
  • CSU/DSU Equipment
  • Routers
  • Fiber Optic Terminals
  • Multiplexers
  • ATM Switches

Design Tools



Pkg Code Details Quantities Dimensions PDF
  • JEDEC Reference: MO-026
  • MSL Pb-Free: L3 @ 260ºC
  • MSL SnPb Eutectic: n/a
  • ThetaJA: 24.0ºC/W
  • Bulk Pack Style: Tray
  • Quantity per Bulk Pack: 60
  • Quantity per Reel: 750
  • Quantity per Tube: n/a
  • Quantity per Tray: 60
  • Reel Size (Dia. x Width x Pitch): 330 x 44 x 32
  • Tape & Reel Unit Orientation: Quadrant 2
  • Dimensions: mm
  • Length: 20
  • Width: 20
  • Thickness: 1.60
  • Lead Pitch: 0.50

Parts & Purchasing

Part Number Pkg Code Min Temp Max Temp Status Buy Now Order Samples
XRT73LC04AIV LQFP144 OBS Suggested:
XRT73LC04AIV-F LQFP144 -40 85 OBS Suggested:
Show obsolete parts
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.

Quality & Environmental Data

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

Additional Quality Documentation may be available, please Contact Support.
Distribution Date Description File
10/27/2018 Product Discontinuation Notice
12/05/2013 Addition of an alternate qualified assembly site, ASE Chung-Li (Taiwan) for assembly using copper or gold wire bonding. Material change and alternate assembly site.
03/19/2013 Product Discontinuation Notification Discontinued.


Search our list of FAQs for answers to common technical questions.
For material content, environmental, quality and reliability questions review the Quality tab or visit our Quality page.
For ordering information and general customer service visit our Contact Us page.

Frequently Asked Questions

The best way to determine this is to go to maxlinear.com and type the part into the search function. At or near the top of the results you should see something that looks like:

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.

The -F suffix indicates ROHS / Green compliance:

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