Perhaps another piece of hitech saved from the dumpster
i in reverse D ,logo on
http://www.aufzu.de/semi/siemens.html
as infineon, perhaps older or IC only logo (don't know German) and the
other pinnings agree with Infineon datasheet. Will get a few from RS ,
but will add an underpad-soldered copper 20mm pcb fuse clip and white
goo around the IC, assuming it will still oscillate etc