Analog Devices Inc./Maxim Integrated DS2148GN+

Overview

DS2148GN+ from Maxim Integrated is a single-channel, 5V E1/T1/J1 Line Interface Unit (LIU) supporting long- and short-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.775 compliance for telecom line interface applications in carrier-grade access equipment.

For engineers reviewing the DS2148GN+ datasheet, DS2148GN+ pinout, DS2148GN+ application, or DS2148GN+ equivalent, key selection considerations include its 49-ball CSBGA (7mm × 7mm) package, dual-mode (NRZ/bipolar) data I/O, programmable line build-out (E1: 0dB/–7.5dB/–15dB/–22.5dB; T1: DSX-1/CSU), and support for 2.048MHz or 1.544MHz master clock inputs.

Technical Context

The DS2148GN+ integrates full analog front-end circuitry-including transformer-coupled RTIP/RRING receivers with automatic sensitivity adjustment (–43dBm E1, –36dBm T1), TTIP/TRING line drivers with configurable output waveshaping, and a PLL-based clock/data recovery engine-enabling direct connection to E1 (2.048Mbps) or T1 (1.544Mbps) physical lines without external timing crystals.

Its architecture supports three control interfaces (8-bit parallel muxed/nonmuxed, 3-wire serial, hardware mode), on-chip PRBS generation/detection (2¹⁵–1 or 2²⁰–1), in-band loop code handling (1–16 bits), and diagnostic features including remote/local/analog loopbacks, error counters, and carrier loss (RCL) detection per ITU-T G.775.

Key Specifications

Pinout & Package

DS2148GN+ uses a 49-ball CSBGA package (7mm × 7mm, RoHS-compliant), pin-compatible with other DS2148G-series variants. Pin assignments are defined for parallel, serial, and hardware modes per Tables 2-2 through 2-7 in the datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS2148GN+, DS2148T+ offers identical electrical performance in a different package and temperature grade, while DS21Q48N delivers four independent LIUs in one device-making it suitable for multi-port systems where channel density outweighs per-channel cost optimization.

Availability

DS2148GN+ is available at Aetrix Electronics and suitable for DSLAM line cards, enterprise T1/E1 gateways, mobile backhaul nodes, and public safety radio base stations requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS2148GN+ 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 high-performance analog, mixed-signal, and power management ICs for communications, industrial, and computing markets.

The DS2148GN+ belongs to Maxim's telecom line interface product line, designed specifically for carrier-class E1/T1 physical layer termination in access and aggregation equipment requiring G.703/G.775 compliance and robust jitter management.

FAQ

What is the operating temperature range for the DS2148GN+?

The DS2148GN+ is rated for industrial operation from –40°C to +85°C. This range is confirmed in the Ordering Information table and supported by thermal characteristics data (θJA = 32°C/W) in Section 9.1 of the datasheet. The "G" suffix denotes the CSBGA package, and "N" indicates lead-free/RoHS compliance; the "+" confirms RoHS status. DS2148GN+ maintains full specification compliance across this entire range without derating.

Does the DS2148GN+ require an external crystal oscillator?

No, the DS2148GN+ does not require an external crystal oscillator. Its crystal-less jitter attenuator uses only a 2.048MHz (or optional 1.544MHz for T1) master clock input at the MCLK pin to generate all internal timing-including recovered clock (RCLK), backplane clock (BPCLK), and jitter-filtered data paths. This eliminates BOM cost and board space associated with discrete oscillators while meeting ITU-T G.823 jitter transfer requirements.

How does the DS2148GN+ handle E1 and T1 line build-out configurations?

The DS2148GN+ supports programmable line build-out via Control Register CCR4. For E1, it selects among 0dB, –7.5dB, –15dB, or –22.5dB outputs per ETSI ETS 300 166; for T1, it configures DSX-1 (short-haul) or CSU (long-haul) profiles with matching attenuation levels. These settings are applied digitally to the internal waveshaping circuitry-no external resistors or jumpers are needed, simplifying layout and enabling runtime reconfiguration.

Can the DS2148GN+ operate in hardware-only mode without a microcontroller?

Yes, the DS2148GN+ supports full hardware mode operation when BIS1 and BIS0 pins are both driven high. In this mode, functions including loopback activation, monitor gain, receive termination, and line build-out are controlled directly by dedicated pins (e.g., HRST*, TEST, PBTS), eliminating the need for firmware or host processor intervention. This mode is documented in Section 3 and Table 2-6 of the datasheet.

What alarm conditions does the DS2148GN+ detect and report?

The DS2148GN+ detects and reports multiple standardized alarms including Receive Carrier Loss (RCL) per ITU-T G.775, Blue Alarm (AIS), Loss of Signal (LOS), and Loss of Transmit Clock (LOTC). These are flagged via the active-low INT* pin and logged in Status Registers (e.g., SR.0–SR.7). RCL detection triggers within 5µs, and AIS is identified by continuous 0x7F octets on the receive path-both verified in Sections 5 and 7.1 of the datasheet.