DS21455N+

Telecom Overview

The DS21455N+ is a quad monolithic T1/E1/J1 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It features four independent transceivers, each comprising a line interface unit (LIU), framer, HDLC controllers, and a TDM backplane interface. The device operates on a single 3.3V supply with 5V tolerant I/O and supports software configuration for T1, E1, or J1 protocols. It utilizes an 8-bit parallel control port compatible with Intel or Motorola bus operations. The component is housed in a 256-pin BGA package measuring 27mm x 27mm and functions within a temperature range of -40°C to +85°C.

Telecom Feature Summary

• Supports complete T1/DS1/ISDN-PRI/J1 and E1/CEPT PCM-30/ISDN-PRI transceiver functionality
• Includes crystal-less jitter attenuator and dual two-frame elastic-store slip buffers
• Features internal software-selectable termination resistors for 75Ω, 100Ω, and 120Ω interfaces
• Integrates dual HDLC controllers and programmable BERT generator/detector

Telecom Applications

• Routers
• Channel Service Units (CSUs)
• Data Service Units (DSUs)
• Muxes
• Switches

Telecom Procurement Notes

Verify the specific suffix 'N+' indicates lead-free/RoHS compliance and extended industrial temperature range (-40°C to +85°C). Confirm the 256-pin BGA package dimensions match the design footprint. Check for any documented errata associated with this revision before finalizing integration.

Telecom Selection Notes

Select the DS21455N+ when a direct replacement for the older DS21Q55 MCM device is required. Ensure the system supports an 8-bit parallel control port for Intel or Motorola bus operations. Verify that the application requires four independent channels with full T1/E1/J1 protocol support.

Telecom Part Context

This component belongs to the DS21455/DS21458 family of quad T1/E1/J1 transceivers. The DS21455 variant specifically uses a larger 27mm BGA package compared to the DS21458's CSBGA. Both devices are software-compatible with legacy parts but feature a unified JTAG controller architecture rather than per-transceiver controllers.

Telecom Replacement Considerations

The datasheet identifies the DS21455 as a direct replacement for the DS21Q55 quad MCM device. Designers should account for the architectural difference where the DS21455 uses a single JTAG controller for all four transceivers.