T1/E1/J1 Long-Haul, Short-Haul Transceiver with Clock Recovery and JA


The XRT83VL38 is a fully integrated Octal (eight channel) long-haul and short-haul line interface unit for T1 (1.544Mbps) 100Ω, E1 (2.048Mbps) 75Ω or 120Ω, J1 110Ω or BITS Timing applications.

In long-haul applications the XRT83VL38 accepts signals that have been attenuated from 0 to 36dB at 772kHz in T1 mode (equivalent of 0 to 6000 feet of cable loss) or 0 to 43dB at 1024kHz in E1 mode.

In T1 applications, the XRT83VL38 can generate five transmit pulse shapes to meet the short-haul Digital Cross-Connect (DSX-1) template requirements as well as for Channel Service Units (CSU) Line Build Out (LBO) filters of 0dB, -7.5dB -15dB and -22.5dB as required by FCC rules. It also provides programmable transmit pulse generators for each channel that can be used for output pulse shaping allowing performance improvement over a wide variety of conditions (The arbitrary pulse generators are available in both T1 and E1 modes).

The XRT83VL38 provides both a parallel/serial Hostmicroprocessor interface as well as a Hardwaremode for programming and control.

Both the B8ZS and HDB3 encoding and decoding functions are selectable as well as AMI. Two on-chip crystal-less jitter attenuators with a 32 or 64 bit FIFO can be placed in the receive and the transmit pathswith loop bandwidths of less than 3Hz. The XRT83VL38 provides a variety of loop-back and diagnostic features as well as transmit driver short circuit detection and receive loss of signal monitoring. It supports internal impedance matching for 75Ω, 100Ω, 110Ω and 120Ω for both transmitter and receiver. In the absence of the power supply, the transmit outputs and receive inputs are tri-stated allowing for redundancy applications The chip includes an integrated programmable clock multiplier that can synthesize T1 or E1 master.

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  • Supports Section 13 - Synchronization Interface in ITU G.703 for both Transmit and Receive Paths
  • Fully integrated eight channel long-haul or short-haul transceivers for E1,T1 or J1 applications
  • Adaptive Receive Equalizer for up to 36dB cable attenuation
  • Programable Transmit Pulse Shaper for E1,T1 or J1 short-haul interfaces
  • Five fixed transmit pulse settings for T1 short-haul applications plus a fully programmable waveform generator for transmit output pulse shaping available for both T1 and E1 modes
  • Transmit Line Build-Outs (LBO) for T1 long-haul application from 0dB to -22.5dB in three 7.5dB steps
  • Selectable receiver sensitivity from 0 to 36dB cable loss for T1 @772kHz and 0 to 43dB for E1 @1024kHz
  • Receive monitor mode handles 0 to 29dB resistive attenuation along with 0 to 6dB of cable attenuation for E1 and 0 to 3dB of cable attenuation for T1 modes
  • Supports 75Ω and 120Ω (E1), 100Ω (T1) and 110Ω (J1) applications
  • Internal and/or external impedance matching for 75Ω, 100Ω, 110Ω and 120Ω
  • Tri-State transmit output and receive input capability for redundancy applications
  • Provides High Impedance for Tx and Rx during power off
  • Transmit return loss meets or exceeds ETSI 300-166 standard
  • On-chip digital clock recovery circuit for high input jitter tolerance
  • Crystal-less digital jitter attenuator with 32-bit or 64-bit FIFO selectable in transmit or receive paths
  • On-chip frequency multiplier generates T1 or E1 Master clocks
  • High receiver interference immunity
  • On-chip transmit short-circuit protection and limiting, and driver fail monitor output (DMO)
  • Receive loss of signal (RLOS) output
  • On-chip HDB3/B8ZS/AMI encoder/decoder functions
  • QRSS pattern generator and detection for testing and monitoring
  • Error and Bipolar Violation Insertion and Detection
  • Receiver Line Attenuation Indication Output in 1dB steps
  • Network Loop-Code Detection for automatic Loop-Back Activation/Deactivation
  • Transmit All Ones (TAOS) and In-Band Network Loop Up and Down code generators
  • Supports Local Analog, Remote, Digital and Dual Loop-Back Modes
  • Meets or exceeds T1 and E1 short-haul and long-haul network access specifications in ITU G.703, G.775, G.736 and G.823; TR-TSY-000499; ANSI T1.403 and T1.408; ETSI 300-166 and AT&T Pub 62411
  • Supports both Hardware and Host (parallel or serial) Microprocessor interface for programming
  • Programmable Interrupt
  • Low power dissipation
  • Logic inputs accept either 3.3V or 5V levels
  • Dual 3.3V and 1.8V Supply Operation
  • 225 ball BGA package
  • -40°C to +85°C Temperature Range


  • BITS Timing
  • T1 Digital Cross-Connects (DSX-1)
  • ISDN Primary Rate Interface
  • CSU/DSU E1/T1/J1 Interface
  • T1/E1/J1 LAN/WAN Routers
  • Public switching Systems and PBX Interfaces
  • T1/E1/J1 Multiplexer and Channel Banks

Design Tools


Pkg Code Details Quantities Dimensions PDF

Parts & Purchasing

Part Number Pkg Code RoHS Min Temp Max Temp Status Buy Now Order Samples
XRT83VL38IB -40 85 OBS Suggested:
XRT83VL38IB-F BGA225 -40 85 OBS Suggested:
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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.
Distribution Date Description File
07/12/2017 Product Discontinuation Notice PDN_17-0626-01-1033.pdf
10/03/2013 Product Discontinuation Notification Discontinued. PDN_13-1003-01-1033.pdf

Frequently Asked Questions

The best way to determine this is to go to exar.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. When you hover over it, it will turn grey and you can click anywhere in the grey box. This brings you to the product page. For example:


Click on Parts & Purchasing, highlighted in yellow 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:


Another method to find out if a part is OBS or EOL is to click on SUPPORT:


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.

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