Analog Devices Inc./Maxim Integrated DS2143QN/T&R

Overview

DS2143QN/T&R from Maxim Integrated (formerly Dallas Semiconductor) is a software-configurable E1 framing transceiver IC designed as a slave/coprocesor to microcontrollers in telecom line interface systems. It performs full E1 frame alignment, CAS/CCS signaling extraction and insertion, CRC4 error detection/generation, HDB3 encoding/decoding, and supports fractional E1, ISDN-PRI, and drop-and-insert applications with 2.048 MHz primary clocking and 5 V CMOS operation.

For engineers reviewing the DS2143QN/T&R datasheet, DS2143QN/T&R pinout, DS2143QN/T&R application, or DS2143QN/T&R equivalent, this page delivers verified technical context, exact register-mapped functionality, elastic store behavior, alarm handling logic, and real-world timing roles for E1 framer integration in carrier-grade access equipment, PRI gateways, and TDM multiplexers.

Technical Context

The DS2143QN/T&R implements an "off-line" framer architecture: all incoming E1 serial data passes through unchanged until framing is applied; receive and transmit paths operate fully independently with separate RCLK/TCLK domains and dual-frame elastic store that can be enabled or bypassed. It supports G.704/G.706/G.732 compliance and provides programmable Sa bit handling, FAS/CRC4 multiframe synchronization, and Si bit access.

Its parallel control port uses an 8-bit multiplexed AD0–AD7 bus with Intel/Motorola timing selectable via BTS pin, and integrates 69 internal registers-including RCR1/RCR2, TCR1/TCR2, CCR, status, signaling, and error counters-for full software-defined configuration of framing format, signaling mode, loopback, HDB3, and alarm reporting via INT1/INT2.

Key Specifications

Pinout & Package

DS2143QN/T&R is packaged in a 44-pin PLCC (plastic leaded chip carrier), 16.5 mm × 16.5 mm body, JEDEC MS-026 variant. Pin 1 marked by corner notch; pin 1 is TCLK (Transmit Clock input).

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2141A and MC145508, DS2143QN/T&R offers superior configurability via 69 registers, essential two-frame elastic store for clock tolerance, and dedicated Sa/Si bit I/O-making it the only choice for ISDN-PRI, fractional E1, and TDM-over-packet timing-critical designs.

Availability

DS2143QN/T&R is available at Aetrix Electronics and suitable for ISDN-PRI gateways, E1 access multiplexers, and fractional E1 drop-and-insert nodes requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for telecom infrastructure deployments.

Supply support for DS2143QN/T&R 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 (acquired by Analog Devices in 2021) is a U.S.-based semiconductor company specializing in precision analog, mixed-signal, and high-reliability ICs for communications, industrial, and automotive markets.

The DS2143QN/T&R belongs to Maxim's legacy telecom timing and framing product line, engineered specifically for E1 line interface applications demanding G.704/G.732 compliance, low-power 5 V CMOS operation, and microcontroller-driven configurability.

FAQ

What is the primary function of the DS2143QN/T&R in an E1 system?

The DS2143QN/T&R serves as a software-configurable E1 framing transceiver that performs frame alignment, CAS/CCS signaling extraction and insertion, CRC4 error handling, HDB3 encoding/decoding, and elastic store buffering. It operates as a coprocessor to a microcontroller, enabling full E1 link management-including alarm detection, Sa/Si bit access, and programmable clock outputs-without requiring external logic. Its role is foundational in ISDN-PRI gateways and E1 access equipment where precise timing and signaling integrity are critical.

Does the DS2143QN/T&R support both CAS and CCS signaling modes?

Yes, the DS2143QN/T&R supports both Channel Associated Signaling (CAS) and Common Channel Signaling (CCS) modes. The selection is controlled by bit CCR.3 in the Common Control Register: setting it to 0 configures CAS mode (for timeslot 16 signaling), while setting it to 1 enables CCS mode. In CAS mode, the device extracts and inserts Sa bits and detects CAS multiframe alignment; in CCS mode, it processes Si bits and supports G.732-compliant signaling structures. Both modes are fully register-programmable and coexist with CRC4 and HDB3 functions.

How does the elastic store in the DS2143QN/T&R improve system robustness?

The DS2143QN/T&R's two-frame elastic store compensates for frequency differences between the incoming E1 line clock (RCLK) and the system clock domain, preventing data loss during clock slips. When enabled (RCR2.1 = 1), it buffers two complete E1 frames and repeats or deletes frames as needed to maintain synchronization-critical in applications like fractional E1 or TDM-over-packet where clock sources are not perfectly aligned. This feature eliminates the need for external FIFOs and simplifies timing design in carrier-grade access equipment.

Can the DS2143QN/T&R generate or detect CRC4 E-bits automatically?

Yes, the DS2143QN/T&R provides automatic CRC4 E-bit detection, counting, and generation. Bit TCR2.1 (AEBE) enables automatic E-bit insertion in the transmit direction, while CRC4 error detection is handled in hardware per G.706. E-bit counters (registers 04h–05h) track errors, and the CRC4 multiframe sync status is reported in SSR.0 (CRC4SA). This offloads CRC4 processing from the host microcontroller and ensures standards-compliant error monitoring without firmware intervention.

What package and packaging format does the DS2143QN/T&R use?

The DS2143QN/T&R is supplied in a 44-pin PLCC (plastic leaded chip carrier) package, specified as DS2143Q in the datasheet, with "N" denoting the PLCC variant and "T&R" indicating tape-and-reel packaging. Its footprint conforms to JEDEC MS-026, measuring 16.5 mm × 16.5 mm with a 1.27 mm pitch. This surface-mount package supports automated assembly and is compatible with industry-standard reflow profiles for telecom PCBs.