GENERAL DESCRIPTION
The XRT83L314 is a fully integrated 14-channel longhaul and short-haul line interface unit (LIU) that operates from a single 3.3V power supply. Using internal termination, the LIU provides one bill of materials to operate in T1, E1, or J1 mode independently on a per channel basis with minimum external components. The LIU features are programmed through a standard microprocessor interface. EXAR’s LIU has patented high impedance circuits that allow the transmitter outputs and receiver inputs to be high impedance when experiencing a power failure or when the LIU is powered off. Key design features within the LIU optimize 1:1 or 1+1 redundancy and non-intrusive monitoring applications to ensure reliability without using relays.

FEATURES
• Fully integrated 14-Channel short haul and long haul transceivers for T1/J1 (1.544MHz) and E1 (2.048MHz) applications.
• T1/E1/J1 short haul, long haul, and clock rate are per port selectable through software without changing components.
• Internal Impedance matching on both receive and transmit for 75Ω (E1), 100Ω (T1), 110Ω (J1), and 120Ω (E1) applications are per port selectable through software without changing components.
• Power down on a per channel basis with independent receive and transmit selection.
• Five pre-programmed transmit pulse settings for T1 short haul applications.
• Arbitrary pulse generator for T1 and E1 modes.
• Transmit line build outs (LBO) for T1 long haul applications from 0dB to -22.5dB in three -7.5dB steps on a per channel basis.
• On-Chip transmit short-circuit protection and limiting protects line drivers from damage on a per channel basis.
• Independent Crystal-Less digital jitter attenuators (JA) with 32-Bit or 64-Bit FIFO for the receive and transmit paths
• On-Chip frequency multiplier generates T1 or E1 master clocks from a variety of external clock sources (8, 16, 56, 64, 128, 256kHz and 1X, 2X, 4X, 8X T1 or E1)
• Driver failure monitor output (DMO) alerts of possible system or external component problems.
• Transmit outputs and receive inputs may be "High" impedance for protection or redundancy applications on a per channel basis.
• Support for automatic protection switching.
• 1:1 and 1+1 protection without relays.
• Selectable receiver sensitivity from 0 to 36dB cable loss in T1 @ 772kHz, and 0 to 43dB cable loss in E1 @ 1,024kHz.
• Receive monitor mode handles 0 to 29dB resistive attenuation (flat loss) along with 0 to 6dB cable loss for both T1 and E1.
• Receiver line attenuation indication output in 1dB steps.
• Loss of signal (RLOS) according to ITU-T G.775/ETS300233 (E1) and ANSI T1.403 (T1/J1).
• Programmable receive slicer threshold (45%, 50%, 55%, or 68%) for improved receiver interference immunity.
• Programmable data stream muting upon RLOS detection.
• On-Chip HDB3/B8ZS encoder/decoder with an internal 16-bit LCV counter for each channel.
• On-Chip digital clock recovery circuit for high input jitter tolerance.
• QRSS pattern generator and detection for testing and monitoring.
• Error and bipolar violation insertion and detection.
• Transmit all ones (TAOS) and in-band network loop up and loop down code generation.
• Automatic loop code detection for remote loopback activation.
• Supports local analog, remote, digital, and dual loopback modes.
• Low Power dissipation: 170mW per channel (50% density).
• 250mW per channel maximum power dissipation (100% density).
• Single 3.3V supply operation (3V to 5V I/O tolerant).
• 304-Pin TBGA package
• -40°C to +85°C Temperature Range
• Supports gapped clocks for mapper/multiplexer applications.

APPLICATIONS
• 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
• Integrated Multi-Service Access Platforms (IMAPs)
• Integrated Access Devices (IADs)
• Inverse Multiplexing for ATM (IMA)
• Wireless Base Stations