Analog Devices Inc./Maxim Integrated DS21354L

Overview

DS21354L from Maxim Integrated is a 3.3V single-chip E1 transceiver (SCT) implementing full CEPT PCM-30/ISDN-PRI line interface functionality, with on-board clock/data recovery from AMI/HDB3 waveforms, 32-bit or 128-bit crystal-less jitter attenuation, dual elastic store buffers, and IEEE 1149.1 JTAG boundary scan - designed for telecom access equipment requiring G.703/G.704/G.823 compliance over 0–2km twisted-pair cables.

For engineers reviewing the DS21354L datasheet, DS21354L pinout, DS21354L application, or DS21354L equivalent, key selection considerations include its 100-pin LQFP package, 3.3V supply operation, independent transmit/receive paths, programmable output clocks for fractional E1/H0/H12, and hardware-based CAS/Sa/Si bit handling in E1 framing and signaling contexts.

Technical Context

The DS21354L integrates a receive-side framer that locates FAS frame and CRC4 multiframe boundaries while detecting RLOS, AIS, RAIS, and remote alarm conditions; its transmit-side formatter independently generates E1-compliant frame/multiframe overhead including CAS, CCS, and CRC4 fields. The device supports both multiplexed and nonmultiplexed 8-bit parallel control ports (Intel/Motorola bus compatible) with register-mapped access to all functional blocks.

Its line interface includes transformer-coupled RRING/RTIP inputs with −43dB receive sensitivity, selectable line build-out for 75Ω coax or 120Ω twisted-pair outputs, and open-drain line driver option. The 8.192MHz clock synthesizer enables asynchronous backplane interfacing, and dual elastic stores operate with independent RSYSCLK/TSYSCLK clocks up to 8.192MHz.

Key Specifications

Pinout & Package

DS21354L is housed in a 100-pin LQFP package (14mm × 14mm, 0.5mm pitch), thermally optimized for telecom line card applications with exposed thermal pad. Pin functions are fully defined per Maxim's DS21354/DS21554 datasheet Rev 021004, Sections 3.1.1–3.1.7.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21554L and MC145508FN, the DS21354L uniquely delivers 3.3V operation with full elastic store buffering, JTAG testability, and hardware Sa/Si bit handling - making it the only choice for modern, low-power, high-integration E1 line cards requiring G.823 jitter compliance and backplane timing decoupling.

Availability

DS21354L is available at Aetrix Electronics and suitable for DSLAM line cards, E1 multiplexers, remote terminal units, and mobile base station controllers requiring stable component supply, long-term lifecycle assurance, and G.703/G.823-certified performance.

Supply support for DS21354L 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 precision analog, mixed-signal, and high-reliability ICs for communications, industrial, and automotive systems.

The DS21354L belongs to Maxim's E1/T1 transceiver product line, engineered specifically for carrier-grade telecom infrastructure requiring robust line interface, deterministic jitter control, and seamless integration with asynchronous backplanes.

FAQ

What is the supply voltage requirement for DS21354L?

The DS21354L operates exclusively from a 3.3V ±5% supply rail. This distinguishes it from the pin-compatible DS21554L, which requires 5V. The 3.3V design reduces power consumption and simplifies integration into modern low-voltage telecom platforms. All I/O pins are 3.3V-tolerant, and the internal regulators condition core logic and analog blocks accordingly. DS21354L does not support dual-supply or mixed-voltage operation.

Does DS21354L support both 75Ω coaxial and 120Ω twisted-pair E1 interfaces?

Yes, DS21354L supports both interface types through programmable line build-out (LBO) settings in the Line Interface Control Register (LICR). For 75Ω coax, it generates G.703-compliant waveshapes with adjustable amplitude and rise/fall times; for 120Ω twisted-pair, it drives transformer-coupled outputs meeting ETS 300 233 short-haul specifications. External transformer selection must match the chosen interface per Table 15-3 in the datasheet.

How does the elastic store function in DS21354L improve system timing robustness?

The DS21354L implements two independent elastic stores - one on the receive path and one on the transmit path - each synchronized to separate backplane clocks (RSYSCLK/TSYSCLK). This allows absorption of frequency/phase differences between recovered E1 timing and asynchronous system clocks, preventing buffer underflow/overflow in multi-slot chassis. Each store uses two-frame depth, enabling seamless handoff across multiframe boundaries without data corruption.

Can DS21354L handle CAS signaling without host processor involvement?

Yes, DS21354L provides full hardware-based CAS signaling extraction and insertion aligned to the CRC-4 multiframe structure. It automatically detects and regenerates FAS, MF, and CAS bits, and can insert user-defined signaling patterns directly via internal registers. This offloads real-time signaling tasks from the host CPU, ensuring deterministic latency and eliminating software-induced jitter in time-critical voice channel applications.

Is JTAG boundary scan supported on DS21354L, and what is its implementation scope?

Yes, DS21354L fully implements IEEE 1149.1 JTAG boundary scan architecture with dedicated TCK, TMS, TDI, TDO, and TRST pins. The boundary scan chain covers all digital I/O pins (including D0–D7, control signals, and alarm outputs) but excludes analog line interface pins (RRING/RTIP/TRING/TTIP) and power/ground. It supports INTEST, SAMPLE/PRELOAD, and EXTEST instructions for production testing and board-level diagnostics.