The Model TISP9110MDM is a programmable overvoltage protection device designed to protect modern dual polarity supply rail ringing SLICs (Subscriber Line Interface Circuits) against overvoltages on the telephone line. Overvoltages can be caused by lightning, AC power contact and induction. Four separate protection structures are used; two positive and two negative to provide optimum protection during Metallic (Differential) and Longitudinal (Common Mode) protection conditions in both polarities. Dynamic protection performance is specified under typical international surge waveforms from Telcordia GR-1089-CORE, ITU-T K.44 and YD/T 950.
The Model TISP9110MDM is programmed by connecting the G1 and G2 gate terminals to the negative (-V(BAT)) and positive (+V(BAT)) SLIC Battery supplies respectively. This creates a protector operating at typically +1.4 V above +V(BAT) and -1.4 V below -V(BAT) under AC power induction and power contact conditions. The protector gate circuitry incorporates 4 separate buffer transistors designed to provide independent control for each protection element. The gate buffer transistors minimize supply regulation issues by reducing the gate current drawn to around 5 mA, while the high voltage base emitter structures eliminate the need for expensive reverse bias protection gate diodes.
The Model TISP9110MDM is rated for common surges contained in regulatory requirements such as ITU-T K.20, K.45, Telcordia GR-1089- CORE, YD/T 950. With the use of appropriate overcurrent protection devices such as the Bourns® Multifuse® and Telefuse™ devices, circuits can be designed to comply with modern telecom standards.