Analog Devices Inc./Maxim Integrated DS2155LC2+

Overview

DS2155LC2+ from Maxim Integrated is a software-selectable T1/E1/J1 single-chip transceiver (SCT) integrating line interface unit (LIU), framer, dual HDLC controllers, and TDM backplane interface. It supports long-haul and short-haul operation, delivers 75Ω/120Ω programmable termination, and provides crystal-less jitter attenuation for telecom line cards. Used in carrier-grade switches and add-drop multiplexers requiring precise clock/data recovery.

For engineers reviewing the DS2155LC2+ datasheet, DS2155LC2+ pinout, DS2155LC2+ application, or DS2155LC2+ equivalent, key selection criteria include software-selectable T1/E1/J1 mode, dual elastic-store slip buffers for asynchronous backplanes up to 16.384MHz, and internal BERT generator/detector for loop testing.

Technical Context

The DS2155LC2+ implements independent transmit and receive paths with G.703-compliant E1 waveform generation for both 75Ω coax and 120Ω twisted-pair media, plus DSX-1 and CSU line buildouts (-7.5dB, -15dB, -22.5dB) for T1. Its LIU includes jitter attenuator, CMI coder/decoder, and software-selectable termination resistors.

It features dual HDLC controllers with FIFO-based packet handling, programmable BERT, and fractional T1/E1 support. The TDM backplane interface operates at 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz - all synthesized to recovered network clock - enabling synchronization across distributed telecom systems.

Key Specifications

Pinout & Package

DS2155LC2+ is housed in a 100-pin LQFP package (14mm × 14mm, 0.5mm pitch) with exposed thermal pad. Pin functions are grouped into transmit interface, receive interface, parallel control port (Intel/Motorola bus compatible), JTAG test access, line interface, supply, and user output pins.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar T1/E1 transceiver applications.

Compared with DS2156LN+, DS2155LC2+ offers identical feature set at commercial temperature grade and lower cost, while MC2155P demands significant software adaptation and sacrifices CMI optical interface capability - making DS2155LC2+ optimal for cost-sensitive, volume T1/E1 line card designs.

Availability

DS2155LC2+ is available at Aetrix Electronics and suitable for T1/E1 line cards, carrier-class switches, and add-drop multiplexers requiring stable component supply, RoHS-compliant packaging, and long-lifecycle support.

Supply support for DS2155LC2+ 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 U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and RF ICs for communications, computing, and industrial markets.

The DS2155LC2+ belongs to Maxim's telecom transceiver product line, designed specifically for carrier-grade T1/E1/J1 line interface applications where integration, jitter performance, and software configurability are critical.

FAQ

What is the operating temperature range for DS2155LC2+?

The DS2155LC2+ is rated for commercial temperature operation from 0°C to +70°C. This specification is defined in the official Maxim Integrated ordering information table and applies to the LQFP package variant with lead-free finish. DS2155LC2+ does not support industrial or extended temperature grades - those are covered by DS2155LN+ and DS2156LN+ variants. Thermal derating is not required within this range when used with proper PCB thermal design.

Does DS2155LC2+ support both T1 and E1 modes simultaneously?

Yes, DS2155LC2+ supports simultaneous T1 and E1 operation on separate channels via its dual-framer architecture. Each channel can be independently configured for T1, E1, or J1 mode through software register writes. This capability is confirmed in the functional description section of the DS2155 datasheet and enables mixed-standard line cards without hardware modification. DS2155LC2+ maintains full HDLC, BERT, and elastic store functionality in either mode.

Is DS2155LC2+ pin-compatible with DS2156?

Yes, DS2155LC2+ is explicitly stated as pin- and software-compatible with the DS2156 in the DS2155 general description. Both share identical 100-pin LQFP footprint, signal naming, and register-level programming model. However, DS2156 adds enhanced jitter attenuation and extended temperature support - meaning DS2155LC2+ can serve as a drop-in replacement in commercial-temp applications where those enhancements are not required.

What clock frequencies does DS2155LC2+ synthesize for the backplane interface?

DS2155LC2+ synthesizes four fixed backplane clock frequencies - 16.384MHz, 8.192MHz, 4.096MHz, and 2.048MHz - all phase-locked to the recovered network clock. This synthesis is performed internally using a programmable clock synthesizer described in Section 30 of the datasheet. The selected frequency is configured via register bits and determines TDM slot timing granularity and data throughput capability.

Does DS2155LC2+ include built-in BERT functionality?

Yes, DS2155LC2+ integrates a fully programmable bit error rate tester (BERT) generator and detector. It supports PRBS patterns (2^7–2^23), error injection, and real-time error counting - all accessible via dedicated registers. This on-chip BERT eliminates need for external test gear during system bring-up and field maintenance. The BERT operates in both network and backplane directions, as verified in Section 26 of the DS2155 datasheet.