Analog Devices Inc./Maxim Integrated DS21Q554BN+

Overview

DS21Q554BN+ from Maxim Integrated (formerly Dallas Semiconductor) is a quad-channel E1 transceiver MCM supporting four independent 2.048 Mbps E1 line interfaces with integrated framer, line interface unit (LIU), elastic stores, and hardware-based signaling. It operates at 5V supply, delivers 8.192 MHz backplane clock output per channel, and supports IEEE 1149.1 JTAG boundary scan. Used in carrier-grade TDM access gateways and multi-service aggregation platforms.

For engineers reviewing the DS21Q554BN+ datasheet, DS21Q554BN+ pinout, DS21Q554BN+ application, or DS21Q554BN+ equivalent, key selection considerations include E1 framing compliance (G.704/G.706), per-channel RLOS/LOTC alarm detection, 256-ball BGA package compatibility, and functional equivalence to DS21554 die-level ICs within the same MCM architecture.

Technical Context

The DS21Q554BN+ integrates four identical DS21554 E1 transceiver dies into a single Multi-Chip Module, each providing full E1 physical layer (TIP/RING analog I/O), framer logic (HDLC controller, per-DS0 channel control), and elastic store buffering. All four channels support independent short-haul and long-haul line interface configurations.

It implements IEEE 1149.1 JTAG for boundary-scan testing across all four SCTs (Sub-Chip Transceivers), with dedicated JTDO outputs per SCT (JTDO2–JTDO4) and shared JTAG control pins. The device omits XTALD, 8XCLK, RDATA, and RCL signals versus the standalone DS21554 to reduce package size-confirming its role as a space-optimized MCM variant rather than a feature-expanded IC.

Key Specifications

Pinout & Package

DS21Q554BN+ uses a 256-ball fine-pitch BGA package (27 mm × 27 mm, 1.27 mm ball pitch), with dedicated power domains (DVDD/DVSS, RVDD/RVSS, TVDD/TVSS) per SCT quadrant and replicated I/O sets for all four transceiver channels.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21Q554BN+, DS21554+T offers identical core E1 transceiver functionality but requires four times the PCB area and external clock management, while MC20288P reduces integration depth by omitting framer logic-making DS21Q554BN+ the sole option for compact, self-contained quad-E1 TDM systems requiring hardware signaling and JTAG testability.

Availability

DS21Q554BN+ is available at Aetrix Electronics and suitable for E1 access gateways, multi-service aggregation routers, and carrier-class ONUs requiring stable component supply across extended product lifecycles.

Supply support for DS21Q554BN+ 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) designs high-performance analog and mixed-signal ICs for communications, computing, and industrial markets.

The DS21Q554BN+ belongs to Maxim's legacy T1/E1 transceiver product line, engineered specifically for space-constrained telecom infrastructure equipment requiring multi-channel E1 line interface, framing, and hardware signaling in a single package.

FAQ

What is the primary function of the DS21Q554BN+ in a telecom system?

The DS21Q554BN+ serves as a quad-channel E1 line interface and framer, providing complete physical layer termination, G.704 frame alignment, HDLC signaling processing, and elastic store buffering for four independent 2.048 Mbps E1 lines. Its integration of four DS21554-equivalent transceivers into one MCM enables compact, high-density TDM access platforms without sacrificing per-channel configurability or alarm monitoring capability.

Does the DS21Q554BN+ support both T1 and E1 standards?

No, the DS21Q554BN+ is specifically an E1 transceiver variant, designed for 2.048 Mbps operation per channel and compliant with ITU-T G.703/G.704 E1 specifications. The T1 counterpart is the DS21Q552BN+, which supports 1.544 Mbps operation. Pin compatibility exists between DS21Q554BN+ and DS21Q552BN+, but electrical characteristics and framing logic are optimized for their respective standards.

How does the DS21Q554BN+ handle clock domain crossing between E1 lines and system logic?

The DS21Q554BN+ uses per-channel elastic stores to buffer incoming E1 data, absorbing phase and frequency variations between line clocks (RCLKx) and system clocks. Each SCT provides independent RCLKI/RCLKO, TCLKI/TCLKO, and RFSYNC/TSYNC signals, allowing precise clock domain isolation. The 8.192 MHz backplane clocks (8MCLK1–8MCLK4) are derived from RCLKx and serve as synchronous references for downstream ASICs or FPGAs handling TDM switching or packetization.

What power supply domains does the DS21Q554BN+ require?

The DS21Q554BN+ requires three distinct power domains per SCT quadrant: DVDD/DVSS for digital logic and framer, RVDD/RVSS for receive analog front-end (TIP/RRING inputs), and TVDD/TVSS for transmit analog output stage (TTIP/TRING). This separation minimizes noise coupling between digital switching and sensitive analog line interface sections, ensuring E1 signal integrity and BER compliance.

Is the DS21Q554BN+ still in active production and supported by Maxim/Analog Devices?

The DS21Q554BN+ is a mature product originally released in 1998 and is now listed as NRND (Not Recommended for New Designs) by Analog Devices. However, Aetrix Electronics maintains active inventory and long-term supply agreements for legacy telecom programs. Full datasheets, application notes, and pin-compatible alternatives remain accessible through Analog Devices' archived documentation portal.