LE57D121BTC

Telecom Overview

The LE57D121BTC is a dual-channel Subscriber Line Interface Circuit (SLIC) from the Le5712 series, designed for high-density POTS applications. It operates with a +5 V logic supply and a negative battery supply ranging from -39 V to -60 V. The device supports loop start and ground start signaling, providing over 20 mA into 2000 Ω loads from -48 V. Key electrical parameters include a standby power consumption of 24 mW per channel and support for 2.0 Vrms metering applications. It features programmable current limits, thermal management via external resistors, and per-channel fault detection. The component is housed in a 44-pin eTQFP package with a 12 x 12 mm footprint.

Telecom Feature Summary

• Integrates two fully featured SLIC channels into a single small-footprint package for high line card density.
• Includes on-chip Thermal Management (TMG) to off-load power dissipation to external resistors during active states.
• Supports multiple control states including Active, Standby, Tip Open, and Disconnect with per-channel fault detection.
• Compatible with 3.3 V or 5 V logic control inputs and supports both Loop Start and Ground Start operations.

Telecom Applications

• Low-cost, high-performance telephone line cards for Central Offices (CO).
• Digital Loop Carrier (DLC) systems requiring compliance with regional standards such as TR-57-CORE.
• POTS applications in markets like India, China, Korea, Japan, Taiwan, and Australia.

Telecom Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to ensure correct packing and variant selection. Confirm that the procurement source is an authorized distributor to guarantee authenticity. Check for any recent product change notices or lifecycle status updates prior to finalizing orders. Ensure compatibility with lead-free assembly processes if required by local regulations.

Telecom Selection Notes

Select this device when designing high-density line cards where board space is limited. Consider the thermal management requirements carefully, as the TMG feature necessitates external resistors to handle power dissipation effectively. Ensure the battery supply voltage falls within the -39 V to -60 V range. Verify that the application requires dual-channel integration and supports the necessary control logic interfaces.

Telecom Part Context

The LE57D121BTC belongs to the Le5712 family of dual-channel SLIC devices manufactured originally by Zarlink Semiconductor, now part of Microchip Technology. This series is engineered to replace older discrete solutions by integrating two channels into one package. It is often paired with QLSLAC codec devices to form complete programmable line circuits for various global telecommunications markets.

Telecom Replacement Considerations

The LE57D121BT is a footprint-compatible alternative within the same family. Designers should verify pinout compatibility and electrical specifications before substitution. Review the Le5711 and Le5712 Comparison Brief Application Note for detailed differences between variants.