Analog Devices Inc./Maxim Integrated DS21FF44

Overview

DS21FF44 from Maxim Integrated is a 16-channel E1 quad framer multichip module (MCM) integrating four DS21Q44 die in a single 300-pin BGA package. It performs frame alignment, CRC-4 checking, signaling extraction/insertion, and HDLC processing for E1 telecommunication lines. Key confirmed parameters: 16 independent E1 channels, 300-pin 27mm × 27mm BGA, 3.3V CMOS with 5V-tolerant I/O, 0°C to +70°C operating range, and IEEE 1149.1 JTAG boundary-scan support. Used in high-density DSLAM line cards.

For engineers reviewing the DS21FF44 datasheet, DS21FF44 pinout, DS21FF44 application, or DS21FF44 equivalent, this page delivers verified technical context, exact pin-to-function mapping, real-world deployment constraints (e.g., absent RLOS/RLINK signals), and validated alternative options for E1 framer consolidation in carrier-grade access equipment.

Technical Context

The DS21FF44 implements four parallel DS21Q44 E1 framer cores in a single MCM, each supporting full E1 framing (2.048 Mbps), CAS/CCS signaling, Sa/Si bit handling, and elastic store-based clock recovery. All core functions-including HDLC controller, DS0 monitoring, and per-channel code generation-are retained from the DS21Q44 die.

Signal consolidation reduces pin count: TSYSCLK and RSYSCLK are internally tied; RFSYNC, RLCLK, RCHCLK, RMSYNC, RLOS, LOTC, TLCLK, TCHCLK, and TCHBLK are omitted. The 4×4 architecture enables concatenation into an 8.192 MHz backplane data stream, supporting dense line-card integration without external multiplexing logic.

Key Specifications

Pinout & Package

DS21FF44 uses a 300-pin MCM BGA package (27 mm × 27 mm, 1.27 mm pitch) with four identical framer quadrants (Framer 1–4), each providing dedicated receive/transmit clock, data, sync, and signaling pins. Power and ground pins are distributed across all quadrants; JTAG, control, and parallel bus pins are shared.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS21FF42 and DS21FT44, the DS21FF44 uniquely delivers full 16-channel E1 framing in a field-proven MCM package-offering the highest E1 line density per square millimeter while maintaining pin compatibility with the DS21FF42 for dual-standard board designs.

Availability

DS21FF44 is available at Aetrix Electronics and suitable for DSLAMs, multiplexers/demultiplexers, and high-density line cards requiring stable component supply, long-term lifecycle assurance, and guaranteed traceability for telecom infrastructure programs.

Supply support for DS21FF44 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 markets.

The DS21FF44 belongs to Maxim's telecom framer product line, designed specifically for carrier-class E1/T1 line interface units requiring high channel density, low power, and standards-compliant framing (G.704, G.706, G.732).

FAQ

What is the primary function of the DS21FF44?

The DS21FF44 is a 16-channel E1 framer multichip module that performs frame synchronization, CRC-4 error checking, CAS/CCS signaling extraction and insertion, and HDLC processing for E1 telecommunications lines. It integrates four DS21Q44 die in a single 300-pin BGA, enabling full 16-line E1 termination without external multiplexing logic. Each channel operates independently at 2.048 Mbps with hardware-based timing recovery.

Is the DS21FF44 pin-compatible with other devices in the same family?

Yes, the DS21FF44 is pin-compatible with the DS21FF42 (16-channel T1 framer) and shares the same 300-pin BGA footprint and control interface. This allows a single PCB layout to support both E1 and T1 variants by changing only firmware and clock configuration. However, DS21FF44 is not compatible with DS21FT44 in terms of channel count-though they share the same package, DS21FT44 has only 12 functional framer channels.

Does the DS21FF44 support JTAG boundary-scan testing?

Yes, the DS21FF44 fully implements IEEE 1149.1 JTAG boundary-scan architecture with dedicated JTCLK, JTMS, JTDI, and JTDOF pins. This enables comprehensive interconnect testing of all 300 BGA balls, verification of framer quadrant connectivity, and in-system debugging of register access paths-critical for high-reliability telecom manufacturing and field diagnostics.

What are the key power supply requirements for the DS21FF44?

The DS21FF44 requires a single 3.3 V digital supply (DVDD) with separate DVDD1–DVDD4 rails per framer quadrant and corresponding DVSS grounds. All I/O pins are 5 V–tolerant, eliminating external level shifters when interfacing with legacy E1 transceivers. Total typical supply current is 1.2 A at 3.3 V under full 16-channel operation, with dynamic power scaling based on active channel count.

Can the DS21FF44 be used in extended temperature applications?

No-the standard DS21FF44 is rated for 0°C to +70°C operation. For extended temperature range, the DS21FF44N variant is available, qualified from –40°C to +85°C. Both share identical functionality and pinout, differing only in process characterization and screening; the 'N' suffix denotes industrial temperature grade and must be specified separately for harsh-environment deployments.