A simple NAND test circuit as follows:
QSPICE results:
LTspice results:
Pspice results:
Change NAND gate to the builtin NAND gate of QSPICE, result as follows;
Is there are something wrong for spice syntax compatibility?
LTspice results:
Pspice results:
It’s probably because QSPICE gates require power and the logic threshold defaults to halfway between VDD and VSS. Other SPICEs don’t do that.