Lab 3 - ECE 421L
Prelab:
- Back-up all of your previous work from the lab and the
course.
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Lab:
In this lab we began with copying
our 10k n-well resistor we created in tutorial 1. The length and width for the
resistor were calculated using a 12.5 lambda to dictate the ratio.
Figure 1
With the length and width
determined above, we can build our resistor and resistor value needed for our
N-well resistor is 10k and as it can be seen when the n-well is extracted the
value of the resistor comes out to 10.21k ohms.
Figure 2
After our resistor has been build
and confirmed for the value wanted, we can start building our DAC. Our DAC is
build using our N-well resistors which will replicated the schematic below. The
N-well resistors are laid out in series and parallel just like the schematic
below.
Figure 3
Each resistor is laid out in
parallel and series just like how our schematic we used for our tutorial 1.
Each pin can also be seen being assigned the same exact way it was in our schematic
going from b0 to b9.
Figure 4
Finally we had to put the DAC
through simulations and confirm the design works. The first simulation is to
DRC the design.
Figure 5
Next we extract our layout. Extracting
it shows us how the values of each resistor come out.
Figure 6
Once the DRC shows no errors and
we have extracted our layout, we can run an LVS to confirm our netlists match and as you can see they do match which means
our design is good.
Figure 7
The netlists
matched as shown in the image below
Figure 8
Simulations:
First simulation is from the
ideal DAC with the ADC schematic. You can observe that both input and output
are on top of each other.
Figure 9
Simulation below is from the DAC
when all pins are set to ground except for pin 9. Also there is a 10pF load on
the output.
Figure 10
Third simulation is for the DAC
and ADC schematic with a 10k ohms load.
Figure 11
Fourth simulation is the same DAC
and ADC schematic except the 10k ohms load is switched out for a 10pF load.
Figure 12
Last simulation is the same
schematic with DAC and ADC except now the 10k ohms resistor and 10pF capacitor
are set in parallel on the output.
