Description
The HC5520 is a Monolithic Subscriber Line Interface Circuit (SLIC) for Analog Subscriber Line cards in Central Office and PABX switches.
   
Features
• Normal and Reversed DC Feed
• Current Limited Loop Feed
• Ringing, Test-In, and Test-Out Relay Drivers
• Thermal Shutdown Protection with Alert Signal
• On-Hook Transmission
• Selectable Transmit and Receive Gain Setting
• Selectable 2-Wire Impedance Matching
• Zero Crossing Ring Trip Detection and Ring Relay
    Release
• Parallel Digital Control and Status Monitoring
• Protection Resistors Inside Feedback Loop Allows the
    Use of PTC Devices Without Impact on Longitudinal
    Balance
• Thermal Management Features
   
Applications
• CO/PABX Line Circuits