Analog Devices Inc./Maxim Integrated DS26401+

Overview

DS26401+ from Maxim Integrated is an octal, software-selectable T1/E1/J1 framer IC with eight independent framer/formatters, full-feature BERT, internal clock adapter (CLAD), and 8-bit parallel control interface configurable for Intel or Motorola bus timing. It operates from a single 3.3V supply with 5V-tolerant inputs and supports line coding including AMI, B8ZS, HDB3, and NRZ. It is used in telecom line cards and WAN interface equipment requiring multi-protocol framing and bit-error testing.

For engineers reviewing the DS26401+ datasheet, DS26401+ pinout, DS26401+ application, or DS26401+ equivalent, key selection criteria include its octal T1/E1/J1 framing capability, integrated BERT mapping flexibility, elastic store buffering per channel, HDLC controller per framer, and support for fractional T1/E1 via gapped-clock mode.

Technical Context

The DS26401+ implements eight independent framer channels, each with dedicated transmit/receive paths, two-frame elastic store buffers, and programmable signaling extraction/insertion. It supports T1 (1.544MHz), E1 (2.048MHz), and J1 framing standards with BOC message control (T1) and Sa/SI bit handling (E1).

Its system interface includes a flexible TDM backplane supporting bus rates from 1.544MHz to 16.384MHz, JTAG test port for boundary scan, and CLAD internal clock generator delivering 16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz outputs - enabling synchronous high-frequency backplane timing without external clock synthesis.

Key Specifications

Pinout & Package

DS26401+ is housed in a 17mm × 17mm, 256-pin fine-pitch BGA package with 1.00mm pitch. Pin assignments are defined per Maxim's official DS26401+ datasheet Rev 072403, covering receive/transmit framer signals, parallel control port (D0–D7, A0–A7, RD, WR, CS, BTS), system interface (TDM bus, CLK, RSYNC, TSSYNC), BERT I/O, JTAG (TCK, TMS, TDI, TDO), and power/ground terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS26401+, DS2155+ offers reduced channel count and no on-chip BERT or clock generation, making it suitable for cost-sensitive quad-port designs; MC2833L matches octal density and BERT but relies on external clocking, increasing system-level timing design complexity.

Availability

DS26401+ is available at Aetrix Electronics and suitable for telecom line cards, WAN interface equipment, and add-drop multiplexers requiring stable component supply, long-term lifecycle support, and guaranteed traceability for carrier-grade deployments.

Supply support for DS26401+ 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 ICs for communications, computing, and industrial applications.

The DS26401+ belongs to Maxim's Telecom Framer product line, designed specifically for carrier-class T1/E1/J1 physical layer interface applications requiring multi-protocol framing, embedded diagnostics, and synchronous backplane integration.

FAQ

What is the primary function of the DS26401+ in telecom systems?

The DS26401+ serves as an octal T1/E1/J1 framer IC that performs physical layer framing, signaling extraction/insertion, alarm detection/generation, and HDLC protocol handling across eight independent channels. It enables line cards and routers to interface with T1, E1, and J1 network lines while supporting backplane TDM interconnects. Its integrated BERT and CLAD clock generator further reduce system-level component count and timing complexity in DS26401+ deployments.

Does the DS26401+ support both T1 and E1 framing simultaneously?

Yes, the DS26401+ supports software-selectable T1, E1, and J1 framing modes per channel. Each of the eight framers can be independently configured for T1 (1.544MHz), E1 (2.048MHz), or J1 operation, allowing mixed-mode line cards. The device complies with ANSI T1.107, ITU-T G.704/G.732, and ARIB STD-28 standards, and handles mode-specific features such as BOC (T1) and Sa/SI bits (E1) without hardware reconfiguration.

What clock frequencies does the internal CLAD generator in the DS26401+ provide?

The DS26401+ internal clock adapter (CLAD) generates four precise output frequencies: 16.384MHz, 8.192MHz, 4.096MHz, and 2.048MHz. These are derived from an external crystal or reference clock and are used to synchronize the TDM backplane interface, eliminating the need for external clock synthesizers. The CLAD output directly drives the system clock input (CLK) and supports H.100 (CT Bus) timing requirements in DS26401+ applications.

How is the BERT functionality implemented in the DS26401+?

The DS26401+ integrates a full-feature BERT (Bit Error Rate Tester) that can be mapped to any of its eight T1/E1 ports via register configuration. It supports pseudorandom pattern generation (2^15–1, 2^23–1), error counting, BER calculation, and error injection. BERT operation is fully independent of framer data paths, enabling in-service link diagnostics without disrupting live traffic - a critical capability verified in DS26401+ field deployments for DSLAM and router maintenance.

What package type and thermal characteristics apply to the DS26401+?

The DS26401+ uses a 17mm × 17mm, 256-pin fine-pitch BGA package with 1.00mm ball pitch and Pb-free (RoHS-compliant) finish. Its thermal resistance (θJA) is 22.5°C/W under standard JEDEC 2-layer board conditions, and maximum junction temperature is +125°C. The device is rated for 0°C to +70°C ambient operation, with validated thermal performance documented in Maxim's DS26401+ Package Information (Rev 072403, Section 17).