Analog Devices Inc./Maxim Integrated DS21554LN+

Overview

DS21554LN+ from Maxim Integrated is a 5V E1 single-chip transceiver (SCT) designed for CEPT PCM-30/ISDN-PRI line interface applications. It performs clock/data recovery from AMI/HDB3 E1 waveforms, provides 32-bit or 128-bit crystal-less jitter attenuation, supports G.703-compliant waveshaping for 75Ω coax and 120Ω twisted-pair, and operates across -40°C to +85°C in a 100-pin LQFP package.

For engineers reviewing the DS21554LN+ datasheet, DS21554LN+ pinout, DS21554LN+ application, or DS21554LN+ equivalent, key selection criteria include E1 framer functionality with FAS/CAS/CCS/CRC4 support, dual elastic store slip buffers for asynchronous backplane interfacing up to 8.192MHz, IEEE 1149.1 JTAG boundary scan capability, and programmable output clocks for fractional E1, H0, and H12 systems.

Technical Context

The DS21554LN+ integrates independent transmit and receive paths with full framer/formatter logic, enabling simultaneous frame alignment, multiframe synchronization, and signaling data extraction/insertion (CAS, Si, Sa bits). Its on-chip jitter attenuator is configurable for either path and selectable between 32-bit or 128-bit depth, supporting compliance with ITU-T G.823 jitter tolerance requirements.

It features an 8-bit parallel control port compatible with both Intel- and Motorola-style buses (multiplexed or nonmultiplexed), direct access to internal registers for real-time configuration, and hardware-based signaling with freeze interrupt generation. The device supports protected line interfaces per ETS 300 011/233 and includes four distinct loopback modes for comprehensive system-level testing.

Key Specifications

Pinout & Package

DS21554LN+ 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 assignments are fully documented in Maxim's DS21354/DS21554 datasheet Section 3.1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21554L and DS21354LN+, the DS21554LN+ uniquely delivers 5V operation with industrial temperature range and full backward compatibility with DS2154/DS2152 pinouts - making it the preferred choice for retrofitting legacy 5V E1 line cards requiring extended thermal reliability.

Availability

DS21554LN+ is available at Aetrix Electronics and suitable for E1 line interface cards, ISDN-PRI gateways, HDSL repeaters, and telecom network monitoring equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for DS21554LN+ 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 U.S.-based semiconductor company specializing in precision analog, mixed-signal, and high-reliability interface ICs for communications, industrial, and automotive markets.

The DS21554LN+ belongs to Maxim's E1/T1 transceiver product line, engineered specifically for CEPT-compliant telecommunications infrastructure where deterministic timing, standards compliance, and field-proven reliability are mandatory.

FAQ

What is the operating voltage range for DS21554LN+?

The DS21554LN+ operates at a nominal 5V supply with ±5% tolerance (4.75V to 5.25V). This fixed 5V requirement distinguishes it from the 3.3V DS21354LN+ variant and ensures compatibility with legacy telecom power architectures. All I/O pins are 5V-tolerant, and the device draws approximately 420mW typical power under full E1 load. DS21554LN+ does not support dual-supply or voltage scaling modes.

Does DS21554LN+ support both FAS and CRC4 multiframe formats?

Yes, DS21554LN+ fully supports both FAS (Frame Alignment Signal) and CRC4 (Cyclical Redundancy Check) multiframe formats, as required by ITU-T G.704 and G.706. The framer automatically detects and locks to either format, and internal registers allow software-selectable configuration for CAS, CCS, or Sa-bit operation within each. DS21554LN+ also provides full access to Si and Sa bits aligned with CRC-4 multiframe boundaries for international signaling applications.

Can DS21554LN+ be used with asynchronous backplane clocks?

Yes, DS21554LN+ includes dual independent elastic store buffers - one on the receive side and one on the transmit side - each accepting RSYSCLK or TSYSCLK inputs up to 8.192MHz. These buffers absorb phase and frequency differences between recovered E1 timing and asynchronous backplane clocks, enabling reliable interconnection to TDM switches, DSPs, or FPGA-based fabric without external clock domain crossing logic. DS21554LN+ supports both byte- and frame-interleave PCM bus modes for multi-SCT synchronization.

Is DS21554LN+ pin-compatible with older Maxim E1 transceivers?

Yes, DS21554LN+ is explicitly pin-compatible with DS2154, DS2152, DS21352, and DS21552 single-chip transceivers, as confirmed in the datasheet Feature list and Pin Configuration section. This allows drop-in replacement in existing designs without PCB layout changes. DS21554LN+ retains identical pin functions, package dimensions (100-pin LQFP), and register mapping - ensuring full hardware and software compatibility with legacy DS2154-based systems.

What line interface standards does DS21554LN+ comply with?

DS21554LN+ complies with ITU-T G.703 (physical layer waveshaping), G.704 (framing structure), G.706 (error detection), G.823 (jitter generation/tolerance), G.732 (line build-out), and I.431 (ISDN-PRI); plus ETSI standards 300 011, 300 233, and 300 166, and CTR12/CTR4. It meets all electrical and timing requirements for 75Ω coax and 120Ω twisted-pair E1 interfaces, including short-circuit current limiting and protected interface operation per ETS 300 233.