#### batistuta

##### Member level 5

**ideal comparator model**

hi,guys

i want to design a SAR ADC, but i don't know how to start, can anybody give me some advices? is there have some tutorial about this topic?

from a paper i see it's step by step: just as follows,

(((The first step of the process is generating

MATLAB code to algorithmically describe the ADC. In this

phase, information about general operation is extracted. The

second step is to generate a complete AHDL model of the

ADC. AHDL blocks such as D flip-flops, a non-clocked

comparator, a non-clocked DAC, and ideal voltage sources are

used in this phase. This model contains no timing information,

but rather verifies circuit functionality. Another benefit of this

phase is that different ADC architecture styles are tested with

little simulation time. At the end of this phase the architecture

of the developed ADC is known. In the third phase, a more

descriptive model of the ADC is built using all AHDL

components. This model uses similar components as the

previous model, however, they contain imperfections such as

rise times, fall times, delay times, finite gains, etc. This model

allows us to adjust these imperfections and observe how theyaffect the performance of the ADC with little simulation time.

For example, INL, DNL, and SNDR are simulated as

functions of these imperfections. Another benefit of this stage

is that all timing analysis is competed and verified. To help in

the designing of the real components typical values are entered

into this model. With the typical values in place we are able to

tweak and arrive at an ADC that meets specifications. This

model helps define the individual specifications for all of the

real components. In the fourth phase, AHDL components are

replaced with their real counterparts. The real components are

designed to the same specifications found in the previous

phase. The replacement process happens one by one. In other

words, one AHDL component is replaced in the AHDL model

and re-simulated. This allows for the testing of the real

components in a working setting. The fifth phase is to run a

completely real transistor level simulation, and verify through

extensive testing, that the SAR is realizable.)))

my question is :

1.when design a ADC, the step always like this? or other method?

2.should i master the MATLAB language and AHDL first? if so,how to start?

thanks.

baggio