حفاظت مدار محدودکننده‌های ولتاژ گذرا (تی وی اس) تریستور محافظ اضافه‌ولتاژ (تی اس اس)

Product Attributes

Introduction

These '61089 parts are all dual forward-conducting buffered p-gate thyristor (SCR) overvoltage protectors. They are designed to protect monolithic SLICs (Subscriber Line Interface Circuits) against overvoltages on the telephone line caused by lightning, a.c. power contact and induction. The '61089 limits voltages that exceed the SLIC supply rail voltage. The '61089 parameters are specified to allow equipment compliance with Telcordia (formally Bellcore) GR-1089-CORE and ITU-T recommendations K.20, K.21 and K.45. The SLIC line driver section is typically powered from 0V (ground) and a negative (battery) voltage. The protector gate is connected to this negative supply. This references the protection (clipping) voltage to the negative supply voltage. The protection voltage will then track the negative supply voltage and the overvoltage stress on the SLiC is minimized. Positive overvoltages are clipped to ground by diode forward conduction. Negative overvoltages are initially clipped close to the SLiC negative supply rail value. If sufficient current is available from the overvoltage, then the protector SCR will switch into a low voltage on-state condition. As the overvoltage subsides the high holding current of '61089 SCR helps prevent d.c. latchup. The '61089 is intended to be used with a series resistance of at least 25 Ω and a suitable overcurrent function for Telcordia compliance. Power fault conditions require a series overcurrent element which either interrupts or reduces the circuit current before the '61089 current rating is exceeded. For equipment compliant to ITU-T recommendations K.20 or K.21 or K.45 only, the series resistor value is set by the coordination requirements. For coordination with a 400 V limit GDT, a minimum series resistor value of 10 Ω is recommended. The '61089 buffered gate design reduces the loading on the SLiC supply during overvoltages caused by power cross and induction. The regular pin-out for surface mount and through-hole packages is a feed through configuration. Connection to the SLiC is made via the '61089 Ring through pins 4 - 5 and Tip through pins 7 - 8. A non-feed-through surface mount (D) package is available. This shunt (SD) version pin-out does not make duplicate connections to pin 5 and pin 8 which increases package creepage distance from ground of the other connections from about 0.7 mm to over 3 mm. High voltage ringing SLICs, with battery voltages below -100 V and down to -155 V, can be protected by the TISP61089B device. Details of this device are in the TISP61089B data sheet.

Features

• Dual Voltage-Tracking Protectors -‘61089 for Battery Voltages to -75V - “61089A for Battery Voltages to -100V
• Low Gate Triggering Current <5mA
• High Holding Current >150mA
• Rated for GR-1089-CORE and K.44 Impulses
• UL Recognized Components
• 2/10 Overshoot Voltage Specified