Solid-state hook switches of Line Card Access Switches (LCAS) have been deployed as a space-saving solution in telephone exchanges since the mid 1990s. These devices are a combination of electronic switches replacing traditional electromechanical relays. The Bourns® TISP4A250H3BJR-S is designed to lower stress to the Le75 series LCAS under AC and lightning impulse conditions and extend the range of TISP4A270H3BJR specifically designed to utilize maximum ringing with other LCAS solutions.
The TISP4A250H3BJ-S has been specifically designed to protect the Le7518x and Le7528x family of Line Card Access Switches (LCAS) and is being recommended as preferred solution. A significant design win occurred as a result in the United States. The TISP4A250H3BJR-S has an asymmetrical voltage characteristic with VDRM/V(BO) characteristics of +100V/_125V and -200 V/-250V. This helps to ensure maximum system voltages may be used while not over-stressing the LCAS switches during over-voltage fault conditions on the telephone line.
The TISP4A250H3BJR-S is manufactured with an ion implant process to provide an accurate voltage protection window in each quadrant. The industry-leading tight VDRM and V(BO) ratio allows for extended ring voltages to be used while still offering LCAS protection.
The TISP4A250H3BJR-S has also been specifically designed to have an impulse rating of 500A 2/10µS and 100A 10/1000µS and can be used with the Bourns® B1250T Telefuse™ to meet the latest Telecordia GR-1089-CORE issue 4 requirements.