DS31256+

Telecom Overview

The DS31256+ is a 256-channel HDLC controller designed for high-throughput telecommunications applications. It supports up to 60 T1 or 64 E1 data streams, or two T3 data streams across 16 physical ports. The device features three fast ports capable of 52Mbps and other ports supporting speeds up to 10Mbps in unchannelized mode. It includes Layer 1 processing, HDLC engines, FIFOs, DMA, and a PCI bus interface. The component operates within a temperature range of 0°C to +70°C and utilizes a 256-pin Plastic BGA package.

Telecom Feature Summary

• Supports 256 independent bidirectional HDLC channels with efficient scatter/gather DMA
• Features integrated on-board bit error-rate tester (BERT) with automatic error insertion capability
• Provides local bus access supporting PCI bridging or direct configuration modes
• Includes receive data packet time-stamping and transmit packet priority setting

Telecom Applications

• Channelized and clear-channel routers with multilink PPP support
• High-density frame-relay access nodes
• xDSL access multiplexers (DSLAMs)
• Triple HSSI interfaces
• SONET/SDH EOC/ECC termination

Telecom Procurement Notes

Verify the specific revision level against the manufacturer's current documentation before procurement. Confirm that the ordering suffix '+' indicates lead-free and RoHS compliance as stated in the datasheet. Ensure the required 256-pin PBGA footprint matches the PCB design specifications. Check for any known errata associated with the specific manufacturing lot or revision date.

Telecom Selection Notes

Select this component when designing systems requiring extensive HDLC channel density, such as handling over 60 T1 lines simultaneously. Consider the availability of three high-speed 52Mbps ports if higher throughput is needed on specific interfaces. Evaluate the need for the integrated BERT functionality for internal loopback testing versus external test equipment requirements.

Telecom Part Context

The DS31256+ belongs to the Envoy family of HDLC controllers from Analog Devices/Maxim Integrated. It serves as a successor to earlier models like the DS3134, offering backward compatibility while providing significantly increased channel capacity and throughput. This device addresses the growing demand for high-density protocol processing in modern telecommunications infrastructure.

Telecom Replacement Considerations

The DS31256 is backward compatible with the DS3134. Verify pinout and register mapping differences when migrating from legacy components. No other direct substitute part numbers are documented in the provided source material.