LE79R70DJCT

Telecom Overview

The LE79R70DJCT is a Ringing Subscriber Line Interface Circuit (RSLIC) from the VE580 Series, manufactured by Microchip Technology. It integrates on-chip ringing and ring-trip detection for short-loop telephony applications. The device operates with VBAT1 ranging from -40 V to -67 V and VBAT2 from -19 V to VBAT1. It features an internal VEE regulator, eliminating the need for an external negative supply. Key electrical parameters include a current gain of 1000, a loop-detect threshold programmable via external components, and two on-chip relay drivers. The component is housed in a 32-pin PLCC package.

Telecom Feature Summary

• Integrates on-chip ringing generation and ring-trip detection to reduce system-level component count.
• Supports battery switching between high and low voltage supplies to optimize power consumption during standby and active states.
• Includes two on-chip relay drivers with snubber circuits for controlling external relays.
• Features an internal VEE regulator that removes the requirement for an external negative power supply.

Telecom Applications

• Integrated Access Devices (IADs)
• Network Interface Units (NIUs)
• ISDN Terminal Adaptors
• Set Top Boxes
• Voice over ISDN or T1/E1 systems

Telecom Procurement Notes

Verify the specific ordering suffix against the manufacturer's documentation to confirm package type and polarity reversal capabilities. Ensure compatibility with lead-free assembly processes, as green package devices utilize matte-tin plating. Confirm that the thermal pad connection requirements are met for proper heat dissipation if utilizing equivalent QFN variants.

Telecom Selection Notes

Select this device for applications requiring integrated ringing functions in short-loop environments such as ISDN-TA or set-top boxes. Consider the bipolar monolithic construction for robust performance. Evaluate the need for polarity reversal support, which may require specific performance grade variants within the family. Ensure the design accommodates the required external R-C networks for impedance programming and ringing waveform shaping.

Telecom Part Context

This component belongs to the Zarlink VE580 series of Subscriber Line Interface Circuits (SLIC). The Le79R70 specifically addresses the need for cost reduction in short-loop telephony by integrating the ringing function on-chip. It is part of a broader family that supports various telephony markets including central office, PBX, and digital loop carrier applications.

Telecom Replacement Considerations

Parts marked with the "Am" prefix are equivalent to those with the "Le" prefix in form, fit, and function. Verify if alternative packages like the 32-pin QFN are suitable substitutes, noting that QFN devices omit the "Le" prefix in marking.