Analog Devices Inc./Maxim Integrated DS21372T

Overview

DS21372T from Maxim Integrated (now Analog Devices) is a 3.3V software-programmable Bit Error Rate Tester (BERT) IC for digital communications test and diagnostics. It performs pseudorandom (up to 2³²−1) and user-defined repetitive pattern generation/detection, supports DC–20 MHz clock rates, features independent transmit/receive paths, 32-bit error/bit counters, and programmable bit error insertion (10⁻¹ to 10⁻⁷). It is used in T1/FT1 loopback testing, CSU/DSU validation, and telecom equipment qualification.

For engineers reviewing the DS21372T datasheet, DS21372T pinout, DS21372T application, or DS21372T equivalent, this page delivers verified functional identity, validated 32-pin TQFP package mapping, confirmed parallel bus interface timing (Intel/Motorola selectable), real-world synchronization behavior (RA0/RA1-assisted sync lock), and precise error injection capability per ITU O.151/O.152/O.153 standards.

Technical Context

The DS21372T implements dual-path architecture with fully independent transmit and receive sections, each clocked by separate gapped-capable inputs (TCLK/RCLK, 0–20 MHz). Its pattern generator uses configurable LFSR topology with programmable polynomial length (1–32 bits) and dual feedback taps (Tap A = PLR, Tap B = PTR), enabling CCITT/ITU-compliant PRBS sequences including 2⁶−1, 2⁹−1, 2¹¹−1, 2¹⁵−1, 2²⁰−1, 2²³−1, and 2³²−1.

Synchronization logic validates incoming patterns against transmitted ones using real-time status flags (SYNC, RLOS, RA0, RA1) and supports manual resync (RESYNC bit) or auto-resync disable (SYNCE bit). Bit error detection operates up to 10⁻² BER, with error counts latched via LC/PCR.4 and reported through four 8-bit BECR registers (BECR0–BECR3).

Key Specifications

Pinout & Package

DS21372T is housed in a 32-pin Thin Quad Flat Package (TQFP) with 0.8 mm pitch, dimensions 9.0 × 9.0 × 1.0 mm (D/E = 8.8–9.2 mm, D1/E1 = 7.0 mm BSC), compliant with JEDEC MO-220.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Bit Error Rate Tester applications.

Compared with DS21372T, DS2141A sacrifices frequency range, voltage compatibility, and programmability for lower cost and simpler integration, while MAX3675 trades MCU controllability and standard compliance for raw speed and signal integrity-neither offers the DS21372T's balance of telecom standard support, embedded diagnostics capability, and field-deployable flexibility.

Availability

DS21372T is available at Aetrix Electronics and suitable for T1/E1 line testing, CSU/DSU validation, Smart Jack diagnostics, router/bridge link verification, and telecom equipment manufacturing requiring stable component supply across industrial temperature ranges.

Supply support for DS21372T 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) designs precision analog, mixed-signal, and digital ICs for instrumentation, communications, and industrial systems, with deep heritage in telecom test solutions.

The DS21372T belongs to Maxim's legacy communications test IC product line, engineered specifically for embedded bit error analysis in carrier-class TDM infrastructure, supporting CCITT/ITU standards and field-serviceable diagnostics.

FAQ

What is the operating temperature range for the DS21372T?

The DS21372T is rated for industrial operation from −40°C to +85°C, matching the DS21372N specification. This range ensures reliable performance in telecom central office environments, outdoor cabinets, and carrier-grade networking equipment where ambient temperatures fluctuate significantly. The DS21372T maintains full DC and AC specifications-including 20 MHz clock operation and 10⁻² BER detection-across this entire range.

Does the DS21372T support both Intel and Motorola parallel bus timing?

Yes, the DS21372T supports both Intel and Motorola bus protocols via the BTS pin (Pin 14). When BTS = 0, it uses Intel timing with ALE, RD, and WR signals; when BTS = 1, it uses Motorola timing with AS, DS, and R/W signals. This dual-mode capability allows seamless integration with diverse microcontrollers and avoids bus interface redesign when migrating between MCU families.

How does the DS21372T achieve synchronization with received patterns?

The DS21372T achieves synchronization by comparing incoming RDATA against the expected pattern using its onboard synchronizer. In pseudorandom mode, it verifies alignment with the configured polynomial; in repetitive mode, it matches pattern length. Sync is declared after 34 + n error-free bits (n = PLR exponent), and real-time status is reported via the SYNC bit (SR.0) and RLOS flag. RA0/RA1 indicators further qualify sync state for debugging.

Can the DS21372T generate the 2²³−1 pattern required by ITU O.151?

Yes, the DS21372T explicitly supports the 2²³−1 pattern per ITU O.151. As shown in Table 4 of the datasheet, this is achieved by programming PTR = 0x11 and PLR = 0x16 while loading PSR registers with 0xFF. The device's LFSR architecture and dual-tap configuration ensure full compliance, enabling certified testing of DS3 and E3 transmission facilities.

What is the function of the LC pin on the DS21372T?

The LC (Load Count) pin (Pin 22) triggers latching of the current bit error count (BECR) and bit count (BCR) values into their respective readable registers while clearing internal counters. A positive-going edge on LC-or setting PCR.4-initiates this atomic operation, enabling precise, jitter-free BER measurement intervals. This hardware-controlled latch eliminates race conditions that could occur with software-only timing.