Analog Devices Inc./Maxim Integrated DS21Q554N

Overview

DS21Q554N from Dallas Semiconductor (now Maxim Integrated) is a quad-channel E1 transceiver Multi-Chip Module (MCM) operating at 5V, integrating four independent DS21554 die for full E1 line interface, framing, alarm handling, and HDLC control per channel. It supports short- and long-haul E1 links, provides per-DS0 channel control, and delivers an 8.192MHz backplane data stream via concatenation. Used in carrier-grade TDM access gateways and E1 multiplexers.

For engineers reviewing the DS21Q554N datasheet, DS21Q554N pinout, DS21Q554N application, or DS21Q554N equivalent, this page delivers verified electrical specifications, validated BGA256 pin mapping, confirmed E1 framer functionality, JTAG boundary-scan support, and real-world alternative selection guidance - all grounded in the December 1998 preliminary datasheet and package documentation.

Technical Context

The DS21Q554N implements four fully independent E1 transceivers in a single MCM, each comprising a line interface unit (LIU), a full-featured framer with elastic stores, hardware signaling support, and HDLC controller. Each channel processes 32 DS0 time slots with configurable alarm detection (RLOS/LOTC), multiframe sync (RMSYNC), and frame sync (RFSYNC).

It uses 5V CMOS technology with 5V-tolerant I/Os, supports IEEE 1149.1 JTAG boundary scan across all four sections (JTCLK, JTDI, JTMS, JTRST, JTDO2–JTDO4), and enables inter-chip concatenation via carry signals (CI1–CI4, CO1–CO4) to form a unified 8.192MHz backplane stream - without requiring external glue logic.

Key Specifications

Pinout & Package

DS21Q554N is housed in a 256-ball MCM BGA package (27mm × 27mm, 1.27mm pitch) with separate DVDD/DVSS, RVDD/RVSS, TVDD/TVSS, and analog tip/ring I/O banks per channel. Power and ground balls are distributed across all four quadrants to minimize noise coupling between SCTs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21Q354 and DS21554, the DS21Q554N uniquely delivers quad-channel E1 functionality in a single 27mm² BGA with hardware concatenation and unified JTAG - making it optimal for high-density carrier access platforms where board area, testability, and deterministic timing are critical.

Availability

DS21Q554N is available at Aetrix Electronics and suitable for central office line cards, E1 access multiplexers, legacy PBX gateways, and network monitoring probes requiring stable component supply and long-term industrial lifecycle support.

Supply support for DS21Q554N 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

Dallas Semiconductor, acquired by Maxim Integrated in 2001, specialized in precision timing, communication interface, and mixed-signal ICs for telecom and industrial infrastructure.

The DS21Q554N belongs to the DS21Qx5x quad transceiver product line, designed specifically for high-density E1/T1 line interface consolidation in carrier-class access equipment - emphasizing integration, signal integrity, and standards compliance over cost-optimized consumer use cases.

FAQ

What is the supply voltage requirement for DS21Q554N?

The DS21Q554N requires a nominal 5V ±5% supply for all digital and analog domains (DVDD, RVDD, TVDD). Its I/O pins are 5V-tolerant, allowing direct connection to standard 5V logic families without level-shifting. The device does not support 3.3V operation - attempting to power DS21Q554N at 3.3V will result in functional failure and potential damage to internal analog circuitry.

Does DS21Q554N support both T1 and E1 standards?

No, DS21Q554N is an E1-only transceiver. It implements ITU-T G.703/G.704/G.732 for 2.048 Mbps E1 operation. For T1 support, Dallas offered the pin-compatible DS21Q552 (5V) or DS21Q352 (3.3V). While DS21Q554N shares the same MCM package and bus interface, its internal framer and LIU are hardwired for E1 framing and line coding - no software or configuration can enable T1 functionality.

How is JTAG boundary scan implemented on DS21Q554N?

DS21Q554N implements IEEE 1149.1 JTAG with one shared controller (JTCLK, JTDI, JTMS, JTRST) and four independent data outputs: JTDO2 (SCT#2), JTDO3 (SCT#3), and JTDO4 (SCT#4); JTDO1 is not exposed. This architecture enables parallel boundary-scan testing of all four transceivers using a single JTAG chain, with each SCT's scan path selectable via address decoding - critical for validating high-density E1 line card assemblies.

Can DS21Q554N be used in concatenated 8.192MHz backplane mode?

Yes, DS21Q554N supports hardware concatenation of all four E1 channels into a single 8.192MHz data stream using CI/CO carry signals (CI1–CI4, CO1–CO4) and synchronized MCLK/RLINK routing. This mode eliminates external FIFOs or glue logic, delivering deterministic latency and phase alignment across all 128 DS0 time slots - essential for time-sensitive TDM-over-packet applications.

What analog interface standards does DS21Q554N support?

DS21Q554N supports balanced 120Ω E1 line interface per channel via differential RTIP/RRING (receive) and TTIP/TRING (transmit) pins. It complies with ITU-T G.703 Section 7 (short-haul) and Section 8 (long-haul) requirements, including adjustable line build-out (LBO) and return loss performance. No external transformers or baluns are required for standard 120Ω twisted-pair connections.