Re: To distribute a current signal instead of a voltage sign
In principal you're alsolutly right. Transfering a voltage accuratly over a chip
is quite difficult. However there are some execeptions. Imagine a voltage reference
for a series of diffamps. Usually the reference voltage is connected to a inputpair
transistor. This however gives us almost no current on the net (if your technology
does not suffer from heavy gate leakage
). Therefore proper shielding or spacing
is good enough here. Having a current on the reference causes a drop, as you have
already mentioned, with all negative side effects
Doing the same with a current mode transfer scheme causes more current
consumption. You need to generate a current wire it all over the chip to the places
you need if and then tranfer it back into a voltage (with local currentmirrors).
This solution is quite nice, but you have to take care about the local gnd level
of the local current mirrors if you're using a n-fet current mirror (vdd for p-fets)
Every solution has it's charm, and I have used both in the past whichout having
problems.
Best Regards
Andi