Switching Gas Discharge Tubes Gas Plasma Voltage Dependent Switches RoHS LT Series The LT Series is a 2-terminal bi-directional, voltage triggered switch is designed for ignition circuits used in high pressure HID lighting. Switching voltages for the devices are fixed depending on the part number selected. The gas plasma trigger technology offers very fast switching speeds, resulting in significantly better di/dt values when compared to silicon based SIDAC devices. Due to the high switching voltage of the devices, step-up transformer sizes and specifications can be reduced saving cost, size and weight. Features • RoHS compliant • Ceramic chamber for ultimate reliability. • Very high switching speed once switching voltage has been reached, resulting in high di/dt to be generated enabling the best performance to be extracted from ignition transformers. • Tape and reel to EIA 481-1 Applications • For switching stored electrical energy (such as capacitive discharge) at predetermined voltages. • Designed for ignition circuits used in high pressure HID lighting. LT xxx SM 8 6 +0.20 - 0.20 +0.20 - 0.20 60.0 +4 LTxxx A Dimensions in mm ORDERING INFORMATION LT 800 VBO Package Type Mechanical Specifications: Weight (ballast ciruit only): 1.42g (0.049oz.) Materials: Electrode Base: Copper alloy Device Marking: Packaging A= Axial lead, tape and Reel SM= Surface Mount 316 w w w. l i t t e l f u s e . c o m Electrode Plating material: Bright Sn Body: Ceramic Littelfuse ‘LF’ marking, voltage and product code (red print) Switching Gas Discharge Tubes Gas Plasma Voltage Dependent Switches RoHS LT Series Device Ratings and Specifications VBO(1) VS (V) (V) VT @ 5A (V) IDRM (2) (A) IBO (3) (mA) CO (4) (pF) VBO to VT (nS) LT230 195 –265 184 – 276 15 1.0 50 2.0 25 LT800 680 – 920 640 - 960 15 1.0 50 2.0 25 7 SWITCH GAS DISCHARGE TUBES Part Number Electrical Life: Switching Cycles (5) ………………………………………………………… 400,000 Peak Discharge Current (5) ………………………………………………………. 400 A Maximum Ratings: Max Switching Frequency ………………………………………………………. 100 Hz Storage Temperature TSTG ……………………………………………………… -40 - +150˚C Operating Temperature ……………………………………………………… -40 - +150˚C Notes: (1) Measured on recommended test circuit (fig 1.) (2) Measured @ 100 Volts DC (3) Current required for transition to on-state (4) Measured @ 1 MHz, zero Volt bias (5) Measured on recommended test circuit (fig 2.) Definitions: VBO – Breakover Voltage VS – Switching Voltage VT @ 5A – Nominal Off-state Voltage at 5A IDRM – Off-state Current IBO – Nominal Breakover Current Co - Max Capacitance VBO to VT – Max switching time from VBO to VT 51KΩ O.C. DC voltage =1000 20KΩ P.V.D. 0.4µH V V 0.22µF 1000Vdc 330nF LT device LT device Fig 1. Recommended breakover voltage test circuit (Discharge current = 10-20mA, sensitivity of Peak Voltage Detect = 10-30mA) Fig 2. Recommended Life Circuit w w w. l i t t e l f u s e . c o m 317