TISP5115H3BJR-S is a forward-conducting unidirectional thyristor overvoltage protector designed for analogue line card and ISDN protection applications. The device features a voltage-triggered thyristor with an anti-parallel diode that limits negative overvoltages through breakdown clamping until the breakover voltage is reached, at which point it crowbars into a low-voltage on state to safely divert surge current. It has a repetitive peak off-state voltage (V_DRM) of -90 V and a breakover voltage (V_(BO)) of -115 V, with a peak pulse surge current rating of 200 A at the 10/700 µs ITU-T K.20/21/45 waveform. The device is rated for 8 kV 10/700 and 200 A 5/310 surge protection, features an ion-implanted breakdown region for precise and stable voltage clamping, and exhibits low voltage overshoot under surge conditions. Common applications include SLIC (Subscriber Line Interface Circuit) protection, ISDN U Interface protection, and ISDN power supply protection in telecommunications equipment.