Analog Devices Inc./Maxim Integrated DS3254+

Overview

DS3254+ from Maxim Integrated (now Analog Devices) is a quad-line interface unit (LIU) for physical-layer interfacing to DS3 (44.736 Mbps), E3 (34.368 Mbps), or STS-1 (51.84 Mbps) telecom lines. It integrates four independent receive/transmit paths, on-chip jitter attenuators with 16/32/64/128-bit FIFO depth, and a clock adapter synthesizing all line-rate clocks from a single input (e.g., 19.44 MHz, 38.88 MHz, or 77.76 MHz). Used in SONET/SDH multiplexers and digital cross-connect systems.

For engineers reviewing the DS3254+ datasheet, DS3254+ pinout, DS3254+ application, or DS3254+ equivalent, key selection considerations include per-port B3ZS/HDB3 encoding/decoding, configurable control interfaces (8-bit parallel, SPI, or hardware mode), jitter attenuation placement flexibility (RX/TX path or disabled), and compliance with ANSI T1.102, ITU G.703, and Telcordia GR-253-CORE.

Technical Context

The DS3254+ implements four fully independent LIU channels, each with separate CDR, AGC/equalizer, and programmable framer interface (binary or bipolar). Each channel supports up to 380 m DS3, 440 m E3, or 360 m STS-1 coaxial cable reach via 75Ω termination.

Its on-chip clock adapter eliminates external oscillators by deriving DS3/E3/STS-1 clocks from one master source (e.g., 19.44 MHz), while jitter attenuators-configurable per channel-meet Telcordia GR-253 and ITU G.823/G.824 requirements for jitter transfer and output jitter when placed in either RX or TX data path.

Key Specifications

Pinout & Package

DS3254+ is housed in a 144-pin, 13 mm × 13 mm thermally enhanced CSBGA (Chip Scale Ball Grid Array) package with 0.8 mm pitch, optimized for high-density telecom line-card layouts and thermal dissipation in fanless chassis.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3254N+ and DS3154+, the DS3254+ offers commercial-temperature operation with full feature parity to DS3254N+, while delivering significant system-level simplification over DS3154+ via integrated clock adapter and jitter attenuator - reducing bill-of-materials, board space, and timing validation effort.

Availability

DS3254+ is available at Aetrix Electronics and suitable for SONET/SDH multiplexers, digital cross-connect systems, and ATM/Frame Relay edge equipment requiring stable component supply across multi-year telecom infrastructure deployments.

Supply support for DS3254+ 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 precision analog, mixed-signal, and high-speed communication ICs for industrial, communications, and computing markets.

The DS3254+ belongs to Maxim's DS325x family of quad-line interface units, designed specifically for carrier-class DS3/E3/STS-1 physical layer interfacing in telecom infrastructure equipment with emphasis on jitter performance, protocol flexibility, and system integration.

FAQ

What is the maximum coaxial cable reach supported by DS3254+ for DS3 signals?

The DS3254+ supports up to 380 meters of 75Ω coaxial cable for DS3 signals, achieved through its integrated automatic gain control (AGC) and adaptive equalizer that compensate for cable loss ranging from 0 dB to 15 dB. This reach complies with ANSI T1.404-1994 and is validated under standard DS3 waveform templates per Table 9-A in the DS3254+ datasheet.

Does DS3254+ support both B3ZS and HDB3 line coding formats?

Yes, DS3254+ supports both B3ZS encoding/decoding for DS3 and HDB3 encoding/decoding for E3 on each of its four LIU channels. The encoding/decoding function is optional and configurable per channel via internal registers or hardware mode pins, ensuring compliance with ANSI T1.107 and ITU G.703 standards.

Can DS3254+ generate all required line-rate clocks from a single input clock?

Yes, DS3254+ includes an on-chip clock adapter that synthesizes all necessary line-rate clocks (DS3, E3, STS-1, OC-3) from a single input clock - such as 19.44 MHz, 38.88 MHz, or 77.76 MHz. This eliminates the need for multiple discrete oscillators and reduces jitter accumulation in the timing path, as confirmed in Section 12 and Table 17-A of the DS3254+ datasheet.

What control interfaces does DS3254+ support, and how are they selected?

DS3254+ supports three control interfaces: 8-bit parallel (Intel or Motorola timing), SPI (up to 10 Mbps), and hardware mode. Selection is determined by the HW pin state (low = CPU mode, high = hardware mode) and, in CPU mode, by the MOT, WR, RD, and ALE pin states. Full timing diagrams and configuration logic are detailed in Sections 5, 15, and 18 of the DS3254+ datasheet.

Is DS3254+ pin-compatible with earlier Maxim LIUs like DS3154+?

Yes, DS3254+ is a drop-in replacement for DS3154+, sharing identical pinout, package (144-pin TE-CSBGA), and software register map. However, DS3254+ adds integrated jitter attenuation and clock adaptation not present in DS3154+, enabling enhanced system-level timing performance without layout changes.