question about memory comparison

[eexuke]

Dear all,
Currently I am choosing severl on-chip memory for my design.I am rather confused about which kinds can I choose. My target is to implement about 10 on-chip memory with each size of several kB.
1)which one is better when considered power(same size),SRAM or DRAM?
2)which one is better when considered cost(same size),SRAM or DRAM?
3)which one is easy to implement, synchronous RAM or asynchronous RAM?
4)If I only want to use 1000B of memory,however,in real design,I have to choose a RAM with size of 1024B?
5)I know usually the RAM is addressed in byte,but can I address the RAM in 4bits?

Many many thanks in advance!

 

[Yun Lin]

I think you fristlly should decide which process you should choose. SRAM and DRAM process is totally different and price is different.

 

[eexuke]

I think you fristlly should decide which process you should choose. SRAM and DRAM process is totally different and price is different.

For example,how about 0.18um or 0.13um process?

 

[andromeda]

Combination of DRAM process with Standard Library Cell process adds several additional mask and is to costly - almost nobody do that.
Even if you still want to use DRAM embedded in your ASIC, you need to know that power consuption for DRAM is much bigger than for SRAM (not acceptable for batery powered devices).
DRAMs are 4-6 times smaller that SRAMs.
There are also options with SRAM-interface-like DRAMs with 'invisible' refreshing part, but power consuming still is the isue. Usage of those DRAM is similary simple as usage of common SRAM.
The important factor in your choise is availability of memory compiler. You could buy from companies like Artisan, Virage, ... Memory Compilers for some particular technology (several 100K$) or to buy memory models only for a few memories you need (20-50K$ per memory).
In any Memory Compiler you could choose memory depth and width, 1-port o 2-port, number of columns (affects physical ratio), speed, etc.