Analog Devices Inc./Maxim Integrated DS21Q58L

Overview

DS21Q58L from Maxim Integrated (now part of Analog Devices) is a quad E1 transceiver IC integrating line interface unit (LIU), framer, and TDM backplane interface for four independent E1/CEPT PCM-30/ISDN-PRI lines. It operates at 2.048MHz per channel, supports FAS/CAS/CRC4 framing, includes crystal-less 32-bit/128-bit jitter attenuators, and delivers 3.3V low-power CMOS performance in telecom infrastructure.

For engineers reviewing the DS21Q58L datasheet, DS21Q58L pinout, DS21Q58L application, or DS21Q58L equivalent, key selection criteria include E1 line count, CAS/CCS signaling support, elastic-store slip buffer capability, 100-pin LQFP package compatibility, and Intel/Motorola/serial host interface flexibility.

Technical Context

The DS21Q58L implements four fully independent E1 transceivers, each with dedicated LIU, framer, and clock/data recovery circuitry. Each channel supports G.703-compliant short-haul line driving (75Ω coax or 120Ω twisted pair), HDB3/AMI line coding, and automatic receive sensitivity adjustment.

Its architecture features dual-path jitter attenuation-dedicated per-channel clock/data jitter attenuators configurable in transmit or receive paths, plus one undedicated hardware-configurable jitter attenuator. The system-level 4/8/16MHz clock synthesizer derives timing from any selected E1 line without external logic.

Key Specifications

Pinout & Package

DS21Q58L is housed in a 100-pin LQFP package (14mm × 14mm), with dedicated analog and digital power/ground domains, four independent E1 analog I/O sets (TTIP/TRING/RTIP/RRING), and multiplexed parallel/serial control interfaces.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21Q58L, DS21Q59 offers identical quad-E1 functionality at lower cost but omits signaling access and improved interrupt handling, while MC3454 provides single-channel flexibility at the expense of higher component count, board area, and missing system-level features like clock synthesis and interleaved bus support.

Availability

DS21Q58L is available at Aetrix Electronics and suitable for DSLAM line cards, routed E1 aggregation systems, IMA backhaul nodes, and WAN service gateways requiring stable component supply, long-term lifecycle assurance, and G.703/G.704 compliance.

Supply support for DS21Q58L 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 semiconductor company specializing in high-performance analog, mixed-signal, and RF solutions for communications, computing, and industrial markets.

The DS21Q58L belongs to Maxim's Telecom Transceiver product line, designed specifically for high-density E1/CEPT line termination in carrier-grade access and aggregation equipment with emphasis on integration, jitter performance, and system-level timing autonomy.

FAQ

What is the operating temperature range for DS21Q58L?

The DS21Q58L is specified for commercial temperature operation from 0°C to +70°C. This range aligns with standard indoor telecom equipment environments such as central office line cards and enterprise edge routers. The DS21Q58LN variant extends this to –40°C to +85°C for extended-temperature applications. DS21Q58L maintains full electrical and timing specifications across its rated range without derating.

Does DS21Q58L support both CAS and CCS signaling?

Yes, DS21Q58L supports both Channel Associated Signaling (CAS) and Common Channel Signaling (CCS) as defined in ITU-T G.704 and ETSI standards. CAS is implemented via FAS multiframe structure with Sa/Si bits, while CCS uses TS16 timeslot allocation. The DS21Q58L includes dedicated registers and interrupt flags for CAS/CCS event detection and generation, enabling full interoperability with legacy and modern telephony switches.

How does the elastic store in DS21Q58L handle asynchronous timing between E1 lines?

The DS21Q58L implements a two-frame elastic-store slip buffer on the receive side to absorb timing differences between asynchronous E1 sources. When a slip condition occurs-such as frequency mismatch or phase drift-the buffer inserts or deletes entire frames to maintain data integrity without corruption. This allows the host system to operate synchronously to a single system clock while accepting four independently timed E1 inputs, critical for IMA and multi-source backhaul applications.

Is DS21Q58L pin-compatible with DS21Q50?

Yes, DS21Q58L is explicitly documented as a direct replacement for DS21Q50, maintaining identical pinout, package (100-pin LQFP), and register map. Key enhancements in DS21Q58L-including signaling access capability and improved interrupt handling-do not affect mechanical or electrical compatibility. Existing DS21Q50 PCB layouts and firmware can be reused with minimal or no modifications when upgrading to DS21Q58L.

What clock sources does DS21Q58L support for system timing?

DS21Q58L supports multiple clock sources: a 2.048MHz master clock (MCLK) input for jitter attenuator operation, selectable E1 line-derived reference clocks (RCLK1–RCLK4), and an internal 4/8/16MHz clock synthesizer. The synthesizer locks to any active E1 line and automatically switches to backup sources upon loss-of-clock detection, ensuring continuous system timing without host intervention. This eliminates need for external clock generators in most deployments.