Hi all,

I am working on the 4 Bit SAR ADC for my Major Project of the UG, if anyone can help me in designing and help me in the simulation part it will be great. My deadline to submit the project to the college is on Monday so if anyone can help me in this it would be great!

 

Hi all,

I am working on the 4 Bit SAR ADC for my Major Project of the UG, if anyone can help me in designing and help me in the simulation part it will be great. My deadline to submit the project to the college is on Monday so if anyone can help me in this it would be great!

This is considered adequate work for an undergraduate degree?

And you need help?

 

This is considered adequate work for an undergraduate degree?

And you need help?

Yes sir, we have not learned about this in our UG program, especially about SAR ADC, so I am finding it difficult.

But i have done a complete literature survey and learnt completely. But finding it difficult to simulate.

 

You have "learnt completely" but yet need someone to design it for you and tell you how to simulate it?

And you haven't started and it is due Monday?

 

Do you know how the SAR algorithm works?
If so explain it in words.

 

You have "learnt completely" but yet need someone to design it for you and tell you how to simulate it?

And you haven't started and it is due Monday?

No I have completed the individual blocks like Sample and hold ckt, Comparator, R - 2R Ladder, and D flip flop is already there in the LT SPICE to build the SAR Logic need the assistance in combining all the blocks in LT SPICE.

 

Do you know how the SAR algorithm works?
If so explain it in words.

Let’s say the input analog voltage is 2.6V, and we are using a 4-bit SAR ADC (which means output ranges from 0000 to 1111, or 0 to 15).

Initialize SAR: Start with the MSB (Most Significant Bit) = 1, rest = 0
→ SAR = 1000 (this = 8 in decimal)

DAC converts SAR to analog:
→ DAC gives 8 × (5 / 15) = 2.67V

Compare:
→ 2.6V (input) < 2.67V → Too high → Clear MSB
→ SAR = 0000

Next bit: Try 0100 (4 in decimal)
→ DAC = 4 × (5/15) = 1.33V → Too low → Keep the bit

Next bit: Try 0110 (6 in decimal)
→ DAC = 6 × (5/15) = 2V → Too low → Keep bit

Next bit: Try 0111 (7 = 2.33V)
→ Still low → Keep bit

Final bit: Try 1000 (8 = 2.67V)
→ 2.6V < 2.67 → Clear bit → Final SAR = 0111

Final Answer: 0111 (7 in decimal)
So, the ADC interprets the analog voltage as 7/15 × 5V = 2.33V, which is the closest digital approximation.