LE77D112BTC

Telecom Overview

The LE77D112BTC is a dual-channel Voice over Subscriber Line Interface Circuit (VoSLIC) manufactured by Microchip Technology, housed in a 44-pin eTQFP package. It implements BORSCHT functions for short/medium loops using integrated buck-boost switching regulators that track line voltage to minimize power dissipation. The device operates with +3.3 V and a nominal +12 V supply, supporting an input range of +8 V to +40 V. It provides up to 90 Vpk balanced ringing for 5 REN loads and supports sinusoidal or trapezoidal waveforms. Six programmable states include Low Power Standby, Disconnect, Normal Active, Reverse Polarity, Ringing, and Line Test.

Telecom Feature Summary

• Integrated dual-channel chip set with built-in boost switching power supply that tracks line voltage to minimize power dissipation
• Supports wide input voltage range from +8 V to +40 V requiring only +3.3 V and nominal +12 V supplies
• Capable of delivering up to 90 Vpk balanced ringing with 5 REN load support
• Includes GR-909 compliant drop test capability for loop length, resistive faults, and foreign electromotive force detection

Telecom Applications

• Voice over IP/DSL Integrated Access Devices and Smart Residential Gateways
• Cable Telephony Network Interface Units (NIU), Set-Top Boxes, and Cable Modems
• Fiber-to-the-Home (FTTH) and Fiber-In-The-Loop (FITL) systems
• Wireless Local Loop and Intelligent PBX applications

Telecom Procurement Notes

Verify the specific ordering suffix 'BTC' corresponds to the green RoHS-compliant package variant as documented in the official datasheet. Confirm compatibility with the required Le78D11 VoSLAC codec interface device, which must be used in conjunction with this SLIC component for full system functionality. Ensure design adherence to the specified external component values for switching regulators and signal conditioning.

Telecom Selection Notes

Select this component for applications requiring high integration of BORSCHT functions in voice over broadband environments. It is suitable for designs aiming to reduce system-level costs, space, and power through minimized external discrete components. Consider the 44-pin eTQFP package constraints and the requirement for a TTL-level clock source driven by the companion Le78D11 device for switcher operation.

Telecom Part Context

The LE77D112BTC belongs to the Zarlink Le77D11 series, now part of Microchip Technology's portfolio following acquisition. This dual-channel VoSLIC device is designed to work as part of a two-device chipset with the Le78D11 VoSLAC. It addresses the requirements of voice over broadband applications by providing a software-configurable solution for subscriber line interfacing.

Telecom Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.