LE57D121BTCT

Telecom Overview

The LE57D121BTCT is a dual-channel Subscriber Line Interface Circuit (SLIC) from the Le5712 family, designed for high-density Plain Old Telephone Service (POTS) applications. It integrates two fully featured line interfaces into a single 44-pin eTQFP package with a 12 x 12 mm footprint. The device supports loop start and ground start operations with battery supplies ranging from -39 V to -60 V. Key electrical characteristics include a programmable current limit capable of supplying over 20 mA into 2000 Ω from -48 V, and low standby power consumption of 24 mW per channel. It features on-chip thermal management to minimize internal power dissipation and supports 2.0 Vrms metering applications.

Telecom Feature Summary

• Dual-channel integration in a compact 44-pin eTQFP package for increased line card density
• On-chip Thermal Management (TMG) feature to off-load power dissipation to external resistors
• Supports multiple control states including Active, Standby, Tip Open, and Disconnect
• Per-channel fault detection and thermal shutdown protection

Telecom Applications

• Low-cost, high-performance central office (CO) line cards
• Digital Loop Carrier (DLC) systems meeting TR-57-CORE requirements
• Telephony applications in regions such as India, China, Korea, Japan, Taiwan, and Australia

Telecom Procurement Notes

Verify the specific ordering suffix 'T' indicates tape and reel packing if required for automated assembly. Confirm that the component originates from Zarlink Semiconductor or its successor entities, as Microchip Technology acquired Zarlink's assets. Ensure the datasheet revision matches the manufacturing batch for accurate pinout and electrical specification alignment.

Telecom Selection Notes

Select this device when board space constraints require integrating two SLIC channels into a single footprint. Consider the thermal management requirements carefully; ensure appropriate external TMG resistors are calculated based on maximum loop current and minimum loop resistance to keep internal power dissipation within safe limits. Verify compatibility with 3.3-V logic control inputs if interfacing with modern microcontrollers.

Telecom Part Context

The LE57D121BTCT belongs to the Le5712 series, which was originally developed by Zarlink Semiconductor. This series serves as a high-density alternative to single-channel SLICs, allowing designers to double the number of lines per board area compared to previous generations like the Le5711. It is often paired with QLSLAC codec devices to form complete programmable line circuits.

Telecom Replacement Considerations

The Le57D121BTC is footprint compatible with Zarlink’s Le5711 Dual SLIC, though functional differences exist between single and dual-channel implementations. Direct replacements must be verified against the specific market requirements (e.g., TR-57-CORE vs. international standards) and metering capabilities.