DS21448

Telecom Overview

The DS21448 is a quad-port E1, T1, or J1 line interface unit (LIU) designed for short-haul and long-haul applications. It integrates four independent transmitters and receivers within a single 144-pin TE-PBGA or 128-pin LQFP package. The device operates on a 3.3V power supply with a voltage range of 3.135V to 3.465V. It supports internal software-selectable receive-side termination for 75Ω, 100Ω, and 120Ω impedances. The component includes a crystal-less jitter attenuator requiring only a 2.048MHz master clock for E1 and T1, with an option for 1.544MHz T1 operation.

Telecom Feature Summary

• Generates G.703 E1 waveshapes and DSX-1/CSU line build-outs for T1 applications
• Supports AMI, HDB3, and B8ZS encoding and decoding
• Includes programmable monitor mode and loopback capabilities
• Features a JTAG boundary scan test port per IEEE 1149.1

Telecom Applications

• Integrated multiservice access platforms
• T1/E1 cross-connects, multiplexers, and channel banks
• Central-office switches and PBX interfaces
• T1/E1 LAN/WAN routers
• Wireless base stations

Telecom Procurement Notes

Verify the specific package type required for the design, as the DS21448 is available in both 144-pin TE-PBGA and 128-pin LQFP configurations. Confirm that the selected variant meets the necessary operating temperature range for the intended environment. Ensure all electrical parameters align with the system's 3.3V power supply specifications before finalizing procurement.

Telecom Selection Notes

Select the appropriate package based on board space constraints and thermal requirements. The 144-pin TE-PBGA offers a compact footprint, while the 128-pin LQFP provides alternative mounting options. Verify compatibility with the host controller's bus interface, as the device supports parallel, serial, and hardware modes. Ensure the master clock source matches the required frequency for the target network standard.

Telecom Part Context

The DS21448 belongs to the Maxim Integrated telecom interface family, specifically designed for digital line interfacing. It serves as a critical component in telecommunications infrastructure, enabling the connection between digital networks and physical transmission lines. Its quad-port architecture allows for efficient integration in high-density equipment designs.

Telecom Replacement Considerations

Check for updated revisions or errata from Analog Devices/Maxim Integrated. Consider the DS21448L+ or DS21448LN+ variants if lead-free compliance or extended temperature ranges are required. Evaluate alternative LIUs from the same manufacturer that offer similar pinouts and functionality.