I'm currently building a DC Bias Option board for my HP 4276A LCZ meter and I am having a little trouble with substituting the old, obsolete and expensive LF13331D Analogue Switch with an in production (and substantially cheaper) TC4066BP Analogue Switch.
I'm sure there's something basic that I am missing here, but I've come to a blank trying to get this to work.
When I made this circuit with the LF13331, it worked perfectly but with the same circuit adjusted to use the TC4066BP, it's just not working..
Basically, every time I plug the TC4066BP on, it pulls the 6.3V rail right down, even if I leave the control pins disconnected.
I've included the original and new schematics below, along with datasheets of both parts. If someone smarter than me can take a look and tell me what I'm doing wrong, that would be greatly appreciated.
The first attachment is my revised schematic, the second is the original HP schematic.