Generally it is as Peter Breuer says. Just check any modern processor, with a BGA package - there can be even tens of GND pins. And the reason is rather functional than for convenience. Most of the pins should be really grounded to ensure proper chip function (from the physical point of view).
May I ask what research you do with a 40-year old microprocessor?
Mr. Petr Kubizňák,
Thank you for your response.....!!
its not about research, we are trying to recollect and strengthen our basics........
Check modern day issues of signal floating as logic travels with no proper ground reference . This is to justify logic swing has to be maintained between (5V, 0V) . They can decline for reasons mentioned by Dr Breuer.
High speed digital devices are power hungry. Although average current consumption may be low, switching of digital circuits requires high current spikes that will produce drops on power line (and raise of ground level). Therefore on modern devices you will find number of GND - Vcc pairs for powering different modules within the chip. They should all be connected to low impedance GND and Vcc plane and decoupled with ceramic low impedance capacitors close to the chip.
Multiple Ground pins contributes to Equipotential Grounding
which reduces interaction of Current Spikes.
Dear M. Shoukath Ali,
8086 microprocessor has 2 GND pins as circuit complexity demands a large amount of current flowing through the circuits, and multiple grounds help in dissipating the accumulated heat, etc.
I hope I have answered your question.
With Best Wishes,
Samir G. Pandya
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