Hello <@U017UPJEGKZ>,
I hope you are doing fine.
F...
# powerj
Jorge Marin
07/28/2022, 7:30 PMHello @Weston Braun,
I hope you are doing fine.
From @Tim Edwards' comment in the chipathon channel, the analog supply and ground pins would be able to stand 300mA current. I was wondering: why did you choose to use analog pins for this in you openPMIC project, "wasting" several analog pins in parallel? Mostly, I'm wondering why do you use 5 pins for the ground terminal. Since we will take part in the chipathon, we will probably be unabke to count with this number of pins, but we still want to achieve 300mA, so we are looking for alternatives.
We would appreciate any info you can provide!
w
Weston Braun
07/28/2022, 8:50 PMI guess part of the answer is that at the time I did not have good figures for the current capacity and assumed it would be equal. If I were to do it again I would devote more pins for the switching node as the metal runner for that is more narrow.
Weston Braun
07/28/2022, 8:52 PMHowever, more power connections are always good. Especially in power electronics when you can have high DI/DT which can cause voltage transients due to the package inductance
Weston Braun
07/28/2022, 8:52 PMI had the control circuitry have an independent VDD connection that was only connected off chip to reduce interference from the power stage
Weston Braun
07/28/2022, 8:58 PMOh, also, at some point I just used all my left over pins for the power stage
Weston Braun
07/28/2022, 9:03 PMAlso, can you link to the comment about the 300mA?
Weston Braun
07/28/2022, 9:04 PMThe bond wire fusing current would be close to 300mA. And 50um*2.3 mA/um = 115mA
Weston Braun
07/28/2022, 9:07 PMAlso, the pins are all routed on M3 only? Tim said he would try to modify the wrapper to route on additional metal layers so I extended all the metal layers to the pin, but not sure if it actually was done
Weston Braun
07/28/2022, 9:07 PMThe power ring for the whole chip gets in the way on some layers
Weston Braun
07/28/2022, 9:08 PMEven with all those I/O pins used up I still have about 250m of interconnect resistance, which is on par with the actual resistance of my switches
j
Jorge Marin
08/02/2022, 8:49 PM@Alfonso Cortés @SebastianNG