Analog Devices Inc./Maxim Integrated DS2155LN

Overview

DS2155LN from Maxim Integrated is a software-selectable T1/E1/J1 single-chip transceiver (SCT) with integrated line interface unit (LIU), framer, dual HDLC controllers, and TDM backplane interface. It operates across -40°C to +85°C, supports 75Ω/120Ω media, delivers crystal-less jitter attenuation, and enables long-haul/short-haul clock/data recovery in telecom line cards and routers.

For engineers reviewing the DS2155LN datasheet, DS2155LN pinout, DS2155LN application, or DS2155LN equivalent, key selection criteria include its software-configurable T1/E1/J1 mode switching, dual elastic-store slip buffers for asynchronous backplanes up to 16.384MHz, programmable termination resistors, CMI coding capability, and JTAG boundary-scan test support.

Technical Context

The DS2155LN implements independent transmit and receive paths with full waveform generation (T1 DSX-1/CSU buildouts; E1 G.703 75Ω/120Ω) and network clock/data recovery. Its LIU includes jitter attenuator, short-circuit/open-circuit detection, and BPV error insertion - all configurable via parallel port.

It integrates dual HDLC controllers with FIFO-based packet handling, programmable BERT generator/detector, and fractional T1/E1 support. The TDM backplane interface accepts 16.384MHz/8.192MHz/4.096MHz/2.048MHz clocks synthesized from recovered network timing.

Key Specifications

Pinout & Package

DS2155LN is housed in a 100-pin LQFP (14mm × 14mm, 0.5mm pitch) package with exposed thermal pad. Pin functions are grouped into transmit/receive line interfaces, 8-bit parallel control port (Intel/Motorola bus compatible), TDM backplane I/O, JTAG test access, and supply rails.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2155LN, DS2156LN offers drop-in upgrade path with expanded E1 signaling and better jitter specs, while MC2155P trades integration for lower BOM cost but sacrifices flexibility and jitter performance - making DS2155LN optimal for multi-standard, crystal-free, high-reliability telecom line cards.

Availability

DS2155LN is available at Aetrix Electronics and suitable for telecom line cards, enterprise routers, and add-drop multiplexers requiring stable component supply across industrial temperature ranges and long product lifecycles.

Supply support for DS2155LN 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 DS2155LN belongs to Maxim's telecom transceiver product line, designed specifically for carrier-class TDM infrastructure requiring software-flexible, multi-standard, crystal-less physical layer interfacing with robust jitter management.

FAQ

What is the operating temperature range of the DS2155LN?

The DS2155LN is rated for industrial operation from -40°C to +85°C. This extended range ensures reliable performance in uncontrolled environments such as outdoor cabinets, central office shelves, and transport equipment. The DS2155LN's thermal design and internal compensation maintain timing accuracy and signal integrity across this full span, unlike commercial-grade variants like DS2155L (0°C to +70°C). DS2155LN is the only version qualified for harsh telecom infrastructure deployments.

Does the DS2155LN require an external crystal oscillator?

No, the DS2155LN features a crystal-less jitter attenuator that derives stable timing directly from the incoming network signal. This eliminates the need for an external crystal, reducing bill-of-materials cost, PCB footprint, and potential failure points. The DS2155LN meets GR-499-CORE jitter transfer and tolerance specifications without external timing components - a key differentiator from alternatives like MC2155P, which mandates a crystal.

How does the DS2155LN support both T1 and E1 standards?

The DS2155LN supports T1, E1, and J1 standards through software-selectable configuration registers - no hardware changes are needed. Its LIU generates T1 DSX-1/CSU waveforms (with -7.5dB, -15dB, -22.5dB buildouts) and E1 G.703 waveshapes for both 75Ω coax and 120Ω twisted-pair media. The DS2155LN's framer and HDLC controllers adapt automatically to the selected standard, enabling single-firmware global deployments.

What is the purpose of the dual elastic-store slip buffers in the DS2155LN?

The DS2155LN includes two independent two-frame elastic-store slip buffers to bridge asynchronous clock domains between the recovered network clock and the system backplane clock (up to 16.384MHz). These buffers absorb timing differences, prevent data loss during clock slips, and enable seamless TDM interconnection in multi-chip line card architectures. This capability is essential for DS2155LN-based designs interfacing with asynchronous switch fabrics or DSP subsystems.

Can the DS2155LN be used in JTAG-boundary-scan test environments?

Yes, the DS2155LN integrates full IEEE 1149.1 JTAG boundary-scan architecture with TCK, TMS, TDI, and TDO pins. It supports instruction register loading, boundary scan register access, and identification register readback - enabling automated PCB test, interconnect verification, and in-system debugging. This JTAG support is standardized across all DS2155 variants, including DS2155LN, and is documented in Section 34 of the official datasheet.