gas plasma voltage dependent switches switching gas discharge tubes 318 www.littelfuse.com 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 ? for switching stored electrical energy (such as capacitive discharge) at predetermined voltages. ? designed for in gas fuel ignition systems and similar circuits. +0.20 - 0.20 +0.20 - 0.20 60.0 6.0 8.0 +4 mechanical specifications: weight: 1.42g (0.049oz.) materials: electrode base: copper alloy electrode plating material: bright sn body: ceramic device marking: littelfuse ?f?marking, voltage and product code rohs
switching gas discharge tubes gas plasma voltage dependent switches 319 www.littelfuse.com 7 switch gas discharge tubes vs series lt device v o.c. dc voltage =1000 0.22 f 51k ? fig 1. recommended breakover voltage test circuit (discharge current = 10-20ma; sensitivity of peak voltage detect = 10-30ma) p.v.d. vs device v 15k ? 2.2 f 32 h 230vac fig 2. recommended life test circuit part number device ratings and specifications v bo (1) (v) v t @ 5a (v) i drm (2) (a) i bo (3) (ma) c o (4) (pf) v bo to v t (ns) vs230 200 ?55 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 electrical life: maximum increase in v bo (1) ?.. 25 v switching operations (6) 2,000,000 maximum ratings: surge on-state current (5) ?1000a storage temperature t stg ?-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 8/20? double exponential pulse (6) measured on recommended test circuit (fig 2.) definitions: v bo ?breakover voltage vt @ 5a ?nominal off-state voltage at 5a i drm ?off-state current i bo ?nominal breakover current c o - max capacitance v bo to v t ?max switching time from v bo to v t rohs
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