B61089QDR Series - Dual port negative voltage programmable battery tracking protection

Roll Over to Zoom
Disclaimer Notice

Littelfuse products are not designed for, and shall not be used for, any purpose (including, without limitation, automotive, military, aerospace, medical, life-saving, life-sustaining or nuclear facility applications, devices intended for surgical implant into the body, or any other application in which the failure or lack of desired operation of the product may result in personal injury, death, or property damage) other than those expressly set forth in applicable Littelfuse product documentation. Warranties granted by Littelfuse shall be deemed void for products used for any purpose not expressly set forth in applicable Littelfuse documentation. Littelfuse shall not be liable for any claims or damages arising out of products used in applications not expressly intended by Littelfuse as set forth in applicable Littelfuse documentation. The sale and use of Littelfuse products is subject to Littelfuse Terms and Conditions of Sale, unless otherwise agreed by Littelfuse. "Littelfuse" includes Littelfuse, Inc., and all of its affiliate entities.

This component is designed to protect two different SLIC (Subscriber Line Interface Card) tip/ring pairs with independent voltage tracking for each pair. This B61089QDR will protect the SLIC interface against lightning induced surge and power fault events. It contains fast switching crowbarring structures for negative events and a simple fast switching diode structure for positive events. It is compatible with the Basic Levels of ITU K.20 and K.21. For compliance with the Enhanced Levels of ITU, TIA 968-B, or GR-1089, an additional series resistor in the tip and ring leads may be required.

The SLIC chipset voltage reference may change as the on-hook/off-hook line condition changes. Therefore, this component is referenced to the - VBAT so that its negative protection threshold follows this changing reference voltage level. This B610989QDR utilizes a transistor gain network so that a low 5 mA current level will activate the thyristor based portion of this protector component during negative events. This also allows an easier turn on during slow rising power fault events. For all positive disturbances, the fast switching diode connected to earth reference will provide the needed protection.


  • Dual port negative voltage tracking programmable component
  • Supports battery voltages down to -170V
  • Low gate triggering current 5 mA max
  • Fails in a short circuit condition when it is surged in excess of its ratings to protect all downstream equipment
  • Surge capability does not degrade after multiple surge events within its ratings
  • High holding current 150 mA min
  • Specified 2/10 limiting voltage
  • Integrated diodes for positive surge protection
  • ESD Immunity(HBM):JESD22 Class 3B, ≥8KV
  • MSL: Level 1 - unlimited
  • RoHS compliant and lead-free


  • Wireless In the Local Loop (WLL)
  • Voice applications which require regenerated POTS
  • VoIP applications
  • PBX
  • FXS applications
  • Digital Pair Gain systems (DPG) and Digital Loop Carrier systems (DLC)
  • Small Office Home Office (SOHO)

Access specifications, certifications, check availability and order parts below

Catalog #VDRM T-R
SizePins T-RCO 2V
IH (mA)Ipp10x1000Ipp2x10Ipp5x310Pins T-GStock

pdf icon Product Selection Guide

Electronics Circuit Protection Product Selection Guide - A guide to selecting Littelfuse circuit protection components for electronic applications...

pdf icon Circuit Protection Technology Application Matrix

Littelfuse is the world leader in the design and manufacturing of fuses for the automotive, industrial, handheld, computer and telecom markets...

pdf icon SIDACtor Catalog

SIDACtor components are solid state crowbar devices designed to protect telecom equipment during hazardous transient conditions...