Analog Devices Inc./Maxim Integrated DS26303LN-75+

Overview

DS26303LN-75+ from Maxim Integrated is an 8-channel short-haul line interface unit (LIU) supporting E1/T1/J1 protocols on a single 3.3V supply, with internal software-selectable termination, crystal-less jitter attenuation, and G.772 nonintrusive monitoring. It integrates on-chip PLL-based clock synthesis for 2.048MHz (E1) or 1.544MHz (T1/J1) rates, supports AMI/HDB3/B8ZS encoding, and delivers AIS detection/generation per ITU-T G.775 and ANSI T1.231 - deployed in E1/T1 multiplexers and wireless base station backhaul interfaces.

For engineers reviewing the DS26303LN-75+ datasheet, DS26303LN-75+ pinout, DS26303LN-75+ application, or DS26303LN-75+ equivalent, key selection considerations include impedance configuration (75Ω default in E1 mode), -40°C to +85°C industrial temperature range, 144-pin eLQFP package with exposed pad, dual-rail/single-rail mode flexibility, and JTAG IEEE 1149.1 boundary scan support for production testability.

Technical Context

The DS26303LN-75+ implements eight independent LIUs with per-channel E1/T1/J1 protocol selection, each featuring integrated transmit front-end with short-circuit protection and receive front-end with peak detector/slicer plus clock and data recovery. Its prescaler PLL accepts external master clocks at multiples of 1.544MHz or 2.048MHz and generates precise line-rate clocks without external crystals.

It supports hardware-mode configuration, 8-bit parallel (Intel/Motorola) or 4-wire serial host interface, and built-in BERT with PRBS-20/PRBS-23 pattern generation and error counting. G.772-compliant nonintrusive monitoring enables real-time signal integrity assessment without service interruption.

Key Specifications

Pinout & Package

DS26303LN-75+ is housed in a 144-pin enhanced LQFP (eLQFP) package with exposed thermal pad (56-G6037-002 outline), optimized for thermal dissipation in high-density telecom line cards. Pin assignments are defined per Figure 4-1 and Table 4-1 of the official datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal line interface unit applications.

Compared with DS26303LN-75+, DS3183 adds framer capability but increases power and complexity, while MC28L34 reduces feature set and temperature range (-20°C to +70°C), making DS26303LN-75+ the optimal choice for industrial-grade, multi-protocol, self-diagnosing E1/T1/J1 line interface needs.

Availability

DS26303LN-75+ is available at Aetrix Electronics and suitable for E1/T1 multiplexers, wireless base station backhaul, ISDN PRI gateways, and ATM/Frame Relay access nodes requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for DS26303LN-75+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in high-performance analog, mixed-signal, and RF solutions for communications, computing, and industrial markets.

The DS26303LN-75+ belongs to Maxim's telecom line interface portfolio, designed specifically for carrier-class short-haul TDM infrastructure requiring protocol flexibility, diagnostic capability, and ruggedized operation.

FAQ

What does the "-75" suffix in DS26303LN-75+ indicate?

The "-75" suffix in DS26303LN-75+ specifies that the device defaults to 75Ω line impedance configuration in E1 mode, aligning with common coaxial E1 infrastructure. This setting is factory-programmed but can be overridden via register writes during initialization. The "+" denotes RoHS-compliant, lead-free packaging with exposed thermal pad - confirmed in Maxim's ordering information table.

Does DS26303LN-75+ support both E1 and T1 protocols simultaneously?

Yes, DS26303LN-75+ supports independent E1, T1, or J1 operation per channel - all eight LIUs can be configured to different protocols concurrently. Each channel's mode is selected via dedicated registers (e.g., LIUx_MODE register), enabling mixed-protocol line cards without external multiplexing logic.

How does the crystal-less jitter attenuator in DS26303LN-75+ function?

The DS26303LN-75+ implements a crystal-less jitter attenuator using a digitally controlled loop filter and PLL architecture, with programmable bandwidth (12–100Hz) per ITU-T G.823. It cleans incoming line-recovered clocks or master reference clocks without requiring external VCXOs, reducing bill-of-materials and board space.

Is JTAG boundary scan supported on DS26303LN-75+?

Yes, DS26303LN-75+ fully implements IEEE 1149.1 JTAG boundary scan with EXTEST, HIGHZ, CLAMP, SAMPLE/PRELOAD, IDCODE, and BYPASS instructions. This enables production test coverage for solder joint integrity and interconnect verification on dense telecom PCBs.

What host interface options does DS26303LN-75+ provide?

DS26303LN-75+ supports three host interface modes: 8-bit parallel (Intel or Motorola timing), 4-wire serial (SPI-like), and hardware-mode configuration via MODESEL pin. Interface selection is determined at power-up and cannot be changed dynamically - verified in Section 4.1 of the datasheet.