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- 21st May 2007, 11:38 #1

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## adc working

In the world, there are three catagories of ADC. I would like to ask what is the working principle of the successive approximate ADC. I get the block diagram but I don't understand the working principle...

thx:)

- 21st May 2007, 11:38

- 21st May 2007, 12:25 #2

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## adc working principle

From this time diagram you can see basic idea. First you test MSB (100000), if it is less than Vin, then MSB=1 else MSB=0. Then you test MSB-1 (110000) from the pisture you can see that it is greater than Vin, so MSB-1=0 (100000). Than you test MSB-2 (101000) from picture it is equal, but you need to test rest of the bits. And so on, and so on.....

- 21st May 2007, 12:25

- 31st May 2007, 13:56 #3

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## successive approximation principle

the working principle is that you set the MSB as 1 and convert it to analog and compare it with the input and if the input is larger than this generated value then it is obvious that the MSB is 1 else it is 0... so you have found the MSB... now u keep the MSB as such and then find MSB-1 place and then so forth.....

- 31st May 2007, 13:56

- 1st June 2007, 08:02 #4

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## adc working

Look through AN 1080 from Maxim

"Understanding SAR ADCs"

http://pdfserv.maxim-ic.com/en/an/AN1080.pdf

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