L8575

· Per-channel ring-trip detectors, loop closure detectors.
· Six relay drivers (three per channel).
· 8-bit serial-to-parallel and parallel-to-serial logic interface.
· Per-channel circuits which eliminate the battery noise that is coupled to the Tip and Ring through the dc feed resistors.
· Fault detection.
· Zero ring voltage detection.

Notes:
Analog and battery voltages are referenced to AGND; digital (logic) voltages are referenced to DGND.

The IC can be damaged unless all ground connections are applied before, and removed after, all other connections. Furthermore, when powering the device, the user must guarantee that no external potential creates a voltage on any pin of the device that exceeds the device ratings. Some of the known examples of conditions that cause such potentials during powering are (1) an inductor connected to Tip and Ring that can force an overvoltage on VBAT through external components if the VBAT connection chatters, and (2) inductance in the VBAT lead that could resonate with the VBAT filter capacitor to cause a destructive overvoltage.

The L8575 is a dual-resistive, low-cost subscriber line interface circuit (SLIC) that is optimized to meet both ITU-T recommendations and LSSGR requirements for 600 /900  resistive and complex impedance termination applications. It interfaces the lowvoltage circuits on an analog line card to the Tip and Ring of two subscriber loops. The L8575 does not supply dc current to the subscriber loops-external resistors are used for this purpose. The device is built using a 90 V complementary bipolar (CBIC) process and is available in a 44-pin PLCC package.