Analog Devices Inc./Maxim Integrated DS3251NA3

Overview

DS3251NA3 from Maxim Integrated (now Analog Devices) is a single-port line interface unit (LIU) for DS3/E3/STS-1 physical-layer interfacing, featuring independent receive/transmit paths, on-chip jitter attenuation, clock adaptation from a single input (e.g., 77.76MHz), B3ZS/HDB3 encoding/decoding, and 3.3V operation with 5V-tolerant I/O. It supports up to 380m DS3 coaxial cable reach and operates across -40°C to +85°C.

For engineers reviewing the DS3251NA3 datasheet, DS3251NA3 pinout, DS3251NA3 application, or DS3251NA3 equivalent, key selection criteria include jitter transfer compliance (Telcordia GR-253, ITU G.823/G.824), hardware/parallel/SPI control interface flexibility, per-channel power-down capability, and drop-in compatibility with legacy DS3151-based designs in telecom infrastructure.

Technical Context

The DS3251NA3 implements a full-duplex DS3/E3/STS-1 LIU with integrated CDR, AGC+adaptive equalizer (0–15dB loss compensation), and dual-mode framer interface (binary/bipolar). Its jitter attenuator is configurable in receive or transmit path with provisionable FIFO depths (16/32/64/128 bits) and overflow/underflow status reporting.

The on-chip clock adapter synthesizes all line-rate clocks-including DS3 (44.736MHz), E3 (34.368MHz), STS-1 (51.84MHz), OC-3 (155.52MHz), and auxiliary rates (19.44/38.88/77.76MHz)-from one master clock, eliminating external oscillators and reducing board space and cost in synchronized telecom systems.

Key Specifications

Pinout & Package

DS3251NA3 is housed in a 144-pin thermally enhanced chip-scale ball grid array (TE-CSBGA), 13mm × 13mm, with 0.8mm pitch and exposed thermal pad. Package supports high-density telecom card layouts and efficient heat dissipation under sustained line-rate operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS3151N+, DS3251NA3 reduces system-level jitter management complexity via its programmable on-chip jitter attenuator and multi-rate clock adapter; compared with TLK2201B, DS3251NA3 offers broader control interface options and superior standards compliance for standalone LIU deployments in carrier infrastructure.

Availability

DS3251NA3 is available at Aetrix Electronics and suitable for SONET multiplexers, digital cross-connects, and DSLAM line cards requiring stable component supply, long-term lifecycle assurance, and industrial temperature operation.

Supply support for DS3251NA3 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

Analog Devices (via acquisition of Maxim Integrated) is a global leader in high-performance analog, mixed-signal, and RF ICs for precision signal processing in communications, industrial, and automotive systems.

The DS3251NA3 belongs to Maxim's legacy telecom line interface portfolio, engineered specifically for carrier-class DS3/E3/STS-1 physical layer interfacing in SONET/SDH, DCS, and broadband access equipment.

FAQ

What telecommunication standards does the DS3251NA3 comply with?

The DS3251NA3 complies with ANSI T1.102, T1.107, T1.231, and T1.404; ITU-T G.703, G.751, G.775, G.823, and G.824; ETSI ETS 300 686/687/EN 300 689; and Telcordia GR-253-CORE and GR-499-CORE. These cover electrical interface, framing, jitter, LOS/AIS detection, and network performance monitoring requirements for DS3/E3/STS-1 systems. DS3251NA3 meets all applicable limits in these standards without external components.

Does DS3251NA3 support both DS3 and E3 line rates simultaneously?

Yes, DS3251NA3 supports DS3 (44.736Mbps), E3 (34.368Mbps), and STS-1 (51.84Mbps) line rates through its integrated clock adapter, which synthesizes required clocks from a single master input (e.g., 77.76MHz). The device configures its receiver CDR and transmitter waveshaping dynamically per selected standard, enabling flexible multi-standard line cards without hardware changes. DS3251NA3 maintains full jitter compliance across all three rates.

How is jitter attenuation configured in DS3251NA3?

Jitter attenuation in DS3251NA3 is configurable via register or hardware pins to operate in the receive path, transmit path, or be disabled. FIFO depth is selectable as 16, 32, 64, or 128 bits, with overflow/underflow status flags reported per channel. The jitter attenuator is crystal-less and meets Telcordia GR-253 and ITU G.823/G.824 output jitter and jitter transfer requirements. DS3251NA3 allows real-time reconfiguration without reset.

What control interfaces does DS3251NA3 support, and how do they differ?

DS3251NA3 supports three control interfaces: hardware mode (pin-strapped configuration), 8-bit parallel (Intel/Motorola configurable), and SPI (≤10Mbps, programmable CPOL/CPHA). Hardware mode provides deterministic, processor-free setup ideal for protection switching; parallel mode offers fastest register access; SPI reduces pin count and supports daisy-chaining. All modes provide identical functional control - DS3251NA3 behavior is identical regardless of interface selected.

Is DS3251NA3 a drop-in replacement for DS3151-based designs?

Yes, DS3251NA3 is a documented drop-in replacement for DS3151/DS3151N+ in 144-pin TE-CSBGA packages, with identical pinout, voltage levels, and timing. It retains all legacy features while adding enhancements including programmable jitter attenuator depth, multi-rate clock synthesis, and SPI interface. No PCB layout changes are required when upgrading from DS3151N+ to DS3251NA3, preserving design investment and accelerating time-to-market.