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Design of General purpose IO library

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dmitryda

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io library design

Hello,

I am starting to design General Purpose IO library and I am new in this area.
Could you please tell me points, to which should I pay special attention?
May be there are books relating to this topic?
If you have some tips relating the design methodology.

I will be happy to see your comments.

Thanks,
Dmitry
 

Hi,

U can try the book.

Basic ESD and I/O Design
by Sanjay Dabral, Timothy Maloney

h**p://
 

Hello lokeyh

Thanks for your input, but looks like the topic was removed.

Do you know other sources for this book?

Thanks,
Dmitry
 

For designing general purpose IO, you need several steps
(1) be familiar with the application since the application determines the spec ALWAYS. If you are not familiar with application, then your IO is goind to be useless finally
(2) IO consists of input buffer and output buffer, separate two cases for design
(3) Input buffer should always have hysteresis level, check how much hysteresis level you need. Sometimes, you need to have control circuit to disable the input buffer to prevent leakage when input is floating
(4) Output buffer includes pre-driver design, buffer design and ESD design. If you have to tolerate high input voltage, high voltage tolerant circuit is required as well
(5) Predriver design requires control logic, slew rate controlled and programmable current source/sink control logic. most of the time, slew rate control is more important. Others are easy
(6) Buffer design includes ESD design, current driving design and ground/VDD boundcing prevention design
(7) High input voltage tolerant circuit is tricky, always need to float NWELL for PMOS to prevent leakage.

Finally, check the IO patents as there are lots of reference designs from other companies
 

Hi,
The attachment shows the simple cmos buffer.
(1)Can you tell me which parameters should be simulated?
(2)Is there any specification examples about this?
(3)Is the output loading is usally 20pF to 50pF?
(4)How to determine the slew rate of the predriver?That is ,what's the usually value of the slew rate?

Thanks a lot!



hung_wai_ming(at)hotmail.com said:
For designing general purpose IO, you need several steps
(1) be familiar with the application since the application determines the spec ALWAYS. If you are not familiar with application, then your IO is goind to be useless finally
(2) IO consists of input buffer and output buffer, separate two cases for design
(3) Input buffer should always have hysteresis level, check how much hysteresis level you need. Sometimes, you need to have control circuit to disable the input buffer to prevent leakage when input is floating
(4) Output buffer includes pre-driver design, buffer design and ESD design. If you have to tolerate high input voltage, high voltage tolerant circuit is required as well
(5) Predriver design requires control logic, slew rate controlled and programmable current source/sink control logic. most of the time, slew rate control is more important. Others are easy
(6) Buffer design includes ESD design, current driving design and ground/VDD boundcing prevention design
(7) High input voltage tolerant circuit is tricky, always need to float NWELL for PMOS to prevent leakage.

Finally, check the IO patents as there are lots of reference designs from other companies
Click to expand...
 

dmitryda said:
Hello,

I am starting to design General Purpose IO library and I am new in this area.
Could you please tell me points, to which should I pay special attention?
May be there are books relating to this topic?
If you have some tips relating the design methodology.

I will be happy to see your comments.

Thanks,
Dmitry
Click to expand...

Here is simple construction of I/O cell
 

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    dmitryda

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