IO,GND and VND supply pads

[khorlipmin]

I have a question. Since in digital chip we will place 3 types of supply pads at each edge, do I need to do the same for analog chip?
I only have 1 input and 3 outputs. So can I just place 4 analog IO pad + 1GND each side + 1VDD each side? the GND and VDD are from analog library as well. Thanks

 

[srivatsan]

Re: IO and supply pad

First of all it may not be right to compare the digital pads to analog pads as they have diverse requirements like voltage and current carrying capability.

From the standpoint of 1 input : 3 output, your arragement should work. However, why do you need more than 1 VDD node? If you need more current, then use opposite locations and join them (dont forget this step). Similarly, put two GND opposite and at max distance from VDD and of course, join them. If you have unused pads, then so be it. Dont fill up pad for the sake of using it. Finally, make sure that you are using the chip area prudently.

I am not sure what is your circuit that you are building, if I know something I can help better.

Let me know whether the above suggestion helped or not...

Srivats

 

[khorlipmin]

IO and supply pad

thanks Srivats, it helps. I think I am gonna use 2 Vdd and 2 gnd distributes at opposite end each edge then 1 IO pad at each edge, making a total of only 2 pads per edge.. cheers!

 

[parthi2311]

Re: IO and supply pad

Hi srivatsan,
I have developed a digital module fully customised using cadence virtuso. My design mainly concentrates on differential interconnects which runs for about 5mm. What should i do for vdd and gnd line. Whether i should use digital vdd pad? If so what does it mean? Please bear it if the question is silly since i have little idea regarding analog vdd and digital vdd. How to add digital vdd?

 

[allanvv]

Re: IO and supply pad

Do you think you should really dredge up posts from 5 years ago?

 

[parthi2311]

Re: IO and supply pad

Do you think you should really dredge up posts from 5 years ago?

yes sir, because i got struck with my project.Please help if you have any relevant material. Thanks in advance

 

[leo_o2]

Re: IO and supply pad

Just place vdd and gnd metal ring around the chip as ESD charging path.
Use digital PAD for digital circuit while use analog PAD for analog circuit.
Add as many as VDD PAD separately around the vdd and gnd metal ring. It will be helpful for ESD.

Hi srivatsan,
I have developed a digital module fully customised using cadence virtuso. My design mainly concentrates on differential interconnects which runs for about 5mm. What should i do for vdd and gnd line. Whether i should use digital vdd pad? If so what does it mean? Please bear it if the question is silly since i have little idea regarding analog vdd and digital vdd. How to add digital vdd?