Switching Gas Discharge Tubes Gas Plasma Voltage Dependent Switches RoHS VS Series The VS Series is a 2-terminal bi-directional, voltage triggered switch designed for gas fuel ignition systems and similar circuits. 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. Applications 8.0 • For switching stored electrical energy (such as capacitive +0.20 - 0.20 discharge) at predetermined voltages. • Designed for in gas fuel ignition systems and similar circuits. +0.20 6.0 - 0.20 60.0 + 4 Mechanical Specifications: Weight: Materials: Device Marking: 318 w w w. l i t t e l f u s e . c o m 1.42g (0.049oz.) Electrode Base: Copper alloy Electrode Plating material: Bright Sn Body: Ceramic Littelfuse ‘LF’ marking, voltage and product code Switching Gas Discharge Tubes Gas Plasma Voltage Dependent Switches RoHS VS Series Device Ratings and Specifications VT @ 5A (V) (V) IDRM (2) (A) IBO (3) (mA) CO (4) (pF) VBO to VT (nS) VS230 200 –255 15 1.0 50 2.0 25 VS450 350 – 550 15 1.0 50 2.0 25 VS600 400 – 750 15 1.0 50 2.0 25 7 SWITCH GAS DISCHARGE TUBES VBO(1) Part Number Electrical Life: Maximum Increase in VBO(1) …………………………………………………... 25 V Switching Operations (6) ………………………………………………………… 2,000,000 Maximum Ratings: Surge On-State Current (5) ……………………………………………………… 1000A Storage Temperature TSTG ……………………………………………………… -40 - +150˚C Operating Temperature ……………………………………………………… -40 - +150˚C Notes: (1) Measured on recommended test circuit (fig 1.) (2) Measured @ 300 Volts DC (3) Current required for transition to on-state (4) Measured @ 1 MHz, zero Volt bias (5) Using 8/20µs double exponential pulse (6) Measured on recommended test circuit (fig 2.) Definitions: VBO – Breakover 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 15KΩ P.V.D. 32µH V V 230Vac 2.2µF 0.22µF VS 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 Test Circuit w w w. l i t t e l f u s e . c o m 319