Analog Devices Inc./Maxim Integrated DS33X161+

Overview

DS33X161+ from Maxim Integrated is a single-port Ethernet-over-PDH mapping IC that encapsulates IEEE 802.3 MAC frames in GFP-F, HDLC, cHDLC, or X.86 for transmission over T1/E1/J1, T3/E3, or xDSL TDM streams. It supports VCAT/LCAS link aggregation across up to 16 TDM links, provides wire-speed bridging and traffic shaping via CIR/CBS policing, and operates across -40°C to +85°C for carrier-grade access equipment.

For engineers reviewing the DS33X161+ datasheet, DS33X161+ pinout, DS33X161+ application, or DS33X161+ equivalent, this device is selected for deterministic Ethernet service delivery over legacy PDH infrastructure-particularly where multi-link inverse multiplexing, OAM frame handling, and QoS-aware GFP-F encapsulation are required.

Technical Context

The DS33X161+ implements a store-and-forward architecture with dual-layer classification: Layer 2 (VLAN ID, 802.1p priority) and Layer 3 (DSCP), enabling per-flow QoS enforcement. Its packet processor handles full GFP-F framing-including core header, payload header, and CRC-16-with optional idle insertion and payload scrambling.

VCAT/LCAS support enables dynamic bandwidth adjustment across up to 16 TDM links with up to 200ms differential delay tolerance. The device interfaces to external 125MHz DDR SDRAM for frame buffering and uses parallel or SPI microprocessor interfaces for configuration and OAM frame extraction/insertion.

Key Specifications

Pinout & Package

DS33X161+ is housed in a 256-ball, 17mm × 17mm CSBGA package (package code: 56-G6017-001) with 0.8mm ball pitch and Pb-free/RoHS-compliant finish. Thermal pad exposed on underside for enhanced heat dissipation in high-throughput carrier applications.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Ethernet-over-PDH mapping applications.

Compared with DS33X162+, DS33X161+ reduces system cost and layout complexity by eliminating redundant MAC logic while retaining full VCAT/LCAS, GFP-F, and OAM functionality. Against DS33X81+, it doubles TDM port density without sacrificing QoS granularity or buffer depth-critical for central office aggregation.

Availability

DS33X161+ is available at Aetrix Electronics and suitable for carrier Ethernet access nodes, TDM-to-Ethernet gateways, and managed service provider edge routers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for DS33X161+ 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 solutions for communications, industrial, and automotive markets.

The DS33X161+ belongs to Maxim's Ethernet-over-PDH mapping product line, designed specifically to enable carrier-grade Ethernet service delivery over legacy TDM infrastructure with full standards compliance and operational visibility.

FAQ

What is the primary function of the DS33X161+ in an Ethernet-over-PDH system?

The DS33X161+ functions as a standards-compliant Ethernet-to-TDM mapper, converting IEEE 802.3 frames into GFP-F, HDLC, cHDLC, or X.86 encapsulated payloads for transport over T1/E1/J1 or T3/E3 circuits. It performs wire-speed bridging, QoS classification, and VCAT/LCAS link aggregation-making DS33X161+ essential for delivering eLAN, eLINE, and VLAN services over legacy PDH networks.

Does the DS33X161+ support both GFP-F and HDLC encapsulation simultaneously?

Yes, the DS33X161+ supports per-port selection of GFP-F, HDLC, cHDLC, or X.86 encapsulation modes. Each of its 16 TDM ports can be independently configured for different protocols, allowing hybrid network deployments-for example, GFP-F for core trunk links and HDLC for legacy interconnects-without requiring separate devices or firmware changes to DS33X161+.

What external memory is required for the DS33X161+ to operate?

The DS33X161+ requires an external 256Mb DDR SDRAM running at 125MHz to serve as its frame buffer and queue management memory. This external memory is mandatory for store-and-forward operation, traffic shaping, and jitter compensation. No internal SRAM buffer exists-DS33X161+ relies entirely on the external DDR interface for all packet storage and forwarding decisions.

How does the DS33X161+ handle OAM frames for service management?

The DS33X161+ provides hardware-accelerated OAM frame handling: it can trap, extract, and insert IEEE 802.3ah and ITU-T Y.1731 OAM frames via its parallel or SPI microprocessor interface. This offloads OAM processing from the host CPU and ensures deterministic timing-critical for SLA monitoring. DS33X161+ does not terminate OAM; it forwards frames to the external processor for interpretation and response.

Is the DS33X161+ pin-compatible with other members of the DS33X family?

No, DS33X161+ is not pin-compatible with DS33X81+ or DS33X41+, though all share the same 256-ball CSBGA package footprint. Pin assignments differ significantly due to varying TDM port counts and internal resource allocation. For example, TDM_RX[15:8] on DS33X161+ map to unused balls on DS33X81+. Board redesign is required when substituting DS33X161+ for lower-port variants.