Hitachi 2SJ217 / 2SK1297 - are these lateral FETs?

Found these in an old Sony car amplifier. They are only good for 60 V and were in fact run from +/- 18.5 V rails. The data sheet does not even recommend them for use in audio amps: "Suitable for motor drive, DC-DC converter, power switch and solenoid drive".

Transconductance and on resistance are pretty low, so are these lateral or vertical FETs?
 
Well it seems from the graphs they are thermally unstable till about 10A current, so would need thermal compensation circuit (laterals normally stable around 100mA which means compensation circuit isn't needed). The transconductance is way higher than most laterals - I think its safe to conclude they aren't lateral. They have rather a lot of input capacitance making driving hard.

Any term like "ultra high xxxx" is clearly marketing, and not a description of the technology used. Every electric motor ever sold is "high torque" for instance...
 
They are indeed verticals (pic 1); list of Hitachi laterals in pic 2 (there are a few more that had already been discontinued when that particular data book was released; off the top of my head: J47-9 / K132-4, J81-83 / K225-7, J96 / K286).
 

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