GENERAL DESCRIPTION
The DS32506 (6 port), DS32508 (8 port), and DS32512 (12 port) line interface units (LIUs) are highly integrated, low-power, feature-rich LIUs for DS3, E3, and STS-1 applications. Each LIU port in these devices has independent receive and transmit paths, a jitter attenuator, full-featured pattern generator and detector, performance-monitoring counters, and a complete set of loopbacks. An on-chip clock adapter generates all line-rate clocks from a single input clock.

FEATURES
■ Pin-Compatible Family of Products
■ Each Port Independently Configurable
■ Receive Clock and Data Recovery for Up to 457 meters (1500 feet) of 75Ω Coaxial Cable
■ Standards-Compliant Transmit Waveshaping
■ Uses 1:1 Transformers on Both Tx and Rx
■ Three Control Interface Options: 8/16-Bit Parallel, SPI, and Hardware Mode
■ Jitter Attenuators (One Per Port) Can be Placed in the Receive Path or the Transmit Path
■ Jitter Attenuators Have Provisionable Buffer Depth: 16, 32, 64, or 128 Bits
■ Built-In Clock Adapter Generates All Line-Rate Clocks from a Single Input Clock (DS3, E3, STS-1, 12.8MHz, 19.44MHz, 38.88MHz, 77.76MHz)
■ Per-Port Programmable Internal Line Termination Requiring Only External Transformers
■ High-Impedance Tx and Rx, Even When VDD = 0, Enables Hot-Swappable, 1:1 and 1+1 Board Redundancy Without Relays
■ Per-Port BERT for PRBS and Repetitive Pattern Generation and Detection
■ Tx and Rx Open and Short Detection Circuitry
■ Transmit Driver Monitor Circuitry
■ Receive Loss-of-Signal (LOS) Monitoring Compliant with ANSI T1.231 and ITU G.775
■ Automatic Data Squelching on Receive LOS
■ Large Line Code Performance-Monitoring Counters for Accumulation Intervals Up to 1s
■ Local and Remote Loopbacks
■ Transmit Common Clock Option
■ Power-Down Capability for Unused Ports
■ Low-Power 1.8V/3.3V Operation (5V Tolerant I/O)
■ Industrial Temperature Range: -40°C to +85°C
■ Small Package: 23mm x 23mm, 484-Pin BGA
■ IEEE 1149.1 JTAG Support

APPLICATIONS
    SONET/SDH and PDH Multiplexers
    ATM and Frame Relay Equipment
    WAN Routers and Switches
    Digital CrossConnects
    Access Concentrators
    CSUs/DSUs
    PBXs
    DSLAMs