AN728
Overview
The efficiency of the converter powering the NT is extremely important, even at power levels of a few milliwatts. To achieve 60% efficiency with an 80-mW output, the allowable power loss in the converter is less than 54 mW.
- Start/Stop Programming The European Telecommunication Standards Institute (ETSI) requires the NT1 and the regenerator directed towards the line terminal to remain at a high impedance state for as long as the input line voltage stays below 18 V. The high impedance state InputCurrent InputVoltage Into +VIN at +VIN A 1.4 m V is defined by the maximum leakage current through the equipment and its minimum input capacitance. In this state the leakage current must be less than 10 mA and the capacitance more than 1 mF. The Si9113 includes a very high input impedance-window comparator, which can be programmed to set an accurate undervoltage lockout (UVLO) level with adequate hysteresis. The programmable hysteresis avoids unintentional locking of the system during start up, especially w
