BBD question

[Haible Juergen]

This may sound stupid, but I'm puzzled about the output stage's
impedance of a typical BBD device like the MN3004.
In the data sheet there are two FETs shown without polarity.
I wonder if these are source followers (low impedance) or
open drain outputs (current source).

What I've put together is this: The supply pin is called "drain voltage",
and it's negative, so the output transistors should be p-channel
FETs connected as source followers. So the chip would be made
in P-MOS technology ? Can anybody confirm this ?

Thanks,

JH.