LE7920-1DJC

Telecom Overview

The LE7920-1DJC is a Subscriber Line Interface Circuit (SLIC) designed for low-cost, high-performance POTS line interface cards. It operates on a single +5 V supply and supports battery voltages from –19 V to –58 V. The device features four control states: Active, Ringing, Standby, and Disconnect. Key electrical parameters include a current gain of 500, standby power consumption of 35 mW, and longitudinal balance ratings of 53 dB or 63 dB depending on the performance grade suffix. It includes programmable constant-current feed, loop-detect thresholds, and ring-trip detect thresholds. The component integrates thermal management capabilities and provides four on-chip relay drivers with snubbers.

Telecom Feature Summary

• Implements basic telephone line interface functions including two-wire impedance synthesis via a single external impedance network.
• Integrates four on-chip relay drivers and relay snubbers, comprising one dedicated ringing driver and three general-purpose drivers.
• Features an on-chip thermal management system that offloads power dissipation to an external resistor during active and disconnect states.
• Provides programmable DC feed current, loop-detect thresholds, and ring-trip detection thresholds without requiring a negative voltage supply.

Telecom Applications

• Design of low-cost, high-performance POTS line interface cards
• Subscriber line interface circuits in telecommunications equipment
• Central office switching systems requiring basic telephone line interface functions

Telecom Procurement Notes

Verify the specific ordering suffix to confirm package type and operating temperature range. The 'D' suffix indicates a green RoHS-compliant package with matte-tin plating, while the standard package uses tin/lead plating. Confirm availability with the manufacturer as valid combinations may vary. Ensure the selected performance grade matches the required longitudinal balance specifications for the application.

Telecom Selection Notes

Select the appropriate performance grade suffix based on required longitudinal balance; '-1' offers 53 dB and '-2' offers 63 dB. Choose the package variant based on environmental regulations, noting that the 'D' suffix denotes a lead-free green package compatible with lead-free assembly processes up to 245°C. Verify that the external programming components for RDC, RD, and ZT networks align with the desired loop current and impedance values specified in the datasheet equations.

Telecom Part Context

The LE7920 is part of the VE580 Series SLIC family originally manufactured by Zarlink Semiconductor Inc., which was later acquired by Legerity and subsequently Microchip Technology. This component serves as a foundational building block for analog telephony interfaces, replacing older discrete designs with an integrated solution that reduces board space and component count.

Telecom Replacement Considerations

Parts marked with the 'Am' prefix are equivalent to those with the 'Le' prefix in form, fit, and function, differing only in the topside marking prefix. No other direct substitute part numbers are documented in the provided datasheet.