Analog Devices Inc./Maxim Integrated DS21348GN+

Overview

DS21348GN+ from Maxim Integrated is a single-channel, 3.3V E1/T1/J1 line interface unit (LIU) supporting both short-haul and long-haul trunks, with software-selectable 75Ω/100Ω/120Ω receive termination, crystal-less jitter attenuation (32-bit or 128-bit FIFO), and full G.703/G.704/G.775 compliance for telecom infrastructure applications.

For engineers reviewing the DS21348GN+ datasheet, DS21348GN+ pinout, DS21348GN+ application, or DS21348GN+ equivalent, key selection criteria include its 49-ball CSBGA package, dual-protocol E1/T1 support, programmable line build-out (0dB to –22.5dB), AMI/HDB3/B8ZS encoding/decoding, and 2.048MHz/1.544MHz master clock flexibility.

Technical Context

The DS21348GN+ integrates full analog front-end circuitry-including active receive equalization, transformer-coupled RTIP/RRING inputs, and TTIP/TRING line drivers-with digital signal processing for clock/data recovery, jitter attenuation, and protocol-specific waveform shaping per ANSI T1.403, ITU G.703, and ETSI ETS 300 166 standards.

Its architecture supports three configurable control interfaces (8-bit parallel muxed/nonmuxed, serial SPI-like, or hardware mode), enables in-band loop code generation/detection (1–16 bits), and provides diagnostic features including PRBS pattern generation/detection, remote/local/analog loopbacks, and real-time error counting via ECR registers.

Key Specifications

Pinout & Package

DS21348GN+ uses a 49-ball CSBGA package (7mm × 7mm, 0.5mm pitch), RoHS-compliant and lead-free (+ suffix). Pin functions are mode-dependent (parallel/serial/hardware); all I/Os are 3.3V-tolerant with internal 50mA RMS current limiting on TTIP/TRING outputs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar line interface unit applications.

Compared with DS21Q348N, DS21348GN+ offers lower power and simpler thermal management for single-port deployments; compared with MAX3005, it delivers modern 3.3V operation, integrated jitter cleanup, and dual-protocol flexibility - reducing total system cost and design cycle time.

Availability

DS21348GN+ is available at Aetrix Electronics and suitable for central office line cards, DSLAM aggregation modules, enterprise PRI gateways, and mobile backhaul radio links requiring stable component supply across extended product lifecycles.

Supply support for DS21348GN+ 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 high-performance analog, mixed-signal, and power management ICs for communications, industrial, and computing markets.

The DS21348GN+ belongs to Maxim's telecom line interface portfolio, engineered specifically for carrier-class E1/T1 physical layer interfacing with emphasis on jitter performance, protocol compliance, and field-deployable reliability.

FAQ

What is the operating temperature range for DS21348GN+?

The DS21348GN+ is rated for industrial operation from –40°C to +85°C, validated per its 49-ball CSBGA package specifications and thermal characteristics in the official datasheet. This range supports deployment in uncontrolled environments such as roadside cabinets and outdoor base stations. DS21348GN+ maintains full G.703 compliance and jitter attenuation performance across this entire span without derating.

Does DS21348GN+ support both E1 and T1 protocols simultaneously?

No - DS21348GN+ operates in either E1 or T1 mode, selected via the ETS bit (CCR1.7); it does not perform concurrent dual-protocol operation. However, mode switching is software-controlled and requires no hardware change. DS21348GN+ implements all required encoding (HDB3/B8ZS), line build-out, and timing parameters for either standard, making it field-upgradeable between E1 and T1 networks.

Can DS21348GN+ generate a backplane clock synchronized to the recovered line clock?

Yes - DS21348GN+ provides BPCLK, a synthesized output clock (16.384MHz, 8.192MHz, 4.096MHz, or 2.048MHz) phase-locked to RCLK. This is configured via CCR5.7 and CCR5.6 and remains stable even during line clock interruptions, enabling use as a jitter-cleaned system timing reference. DS21348GN+'s BPCLK meets G.823 jitter accumulation limits for multi-stage timing distribution.

How does DS21348GN+ handle receive carrier loss detection?

DS21348GN+ implements G.775-compliant Receive Carrier Loss (RCL) detection via the RCL/LOTC pin, which toggles high when signal amplitude falls below programmable thresholds (0dB to –43dB for E1). The condition is latched in Status Register 1 (RIR1.7) and can trigger the INT pin. DS21348GN+ also supports Loss of Transmit Clock (LOTC) detection when TCLK stalls for >5µs - both functions are independently configurable.

Is external termination required for DS21348GN+ when interfacing with 75Ω coaxial E1 lines?

No - DS21348GN+ includes internal software-selectable 75Ω receive termination, activated via CCR2.5–CCR2.4. This eliminates external resistors and PCB layout dependencies for 75Ω applications. For 120Ω balanced E1 or T1, DS21348GN+ supports internal 100Ω/120Ω termination or external termination; the device automatically adjusts equalization gain based on selected impedance.