Need help on ADC design

[vetriselvan]

Hi,
My input to diff amp is 2V and 1V Dc supply.and the output from the diff amp is 0-5V.This output going to ADC.My requirement is 12 bit parallel or serial ADC.Can someone help me to choose the ADC and provide me the full schematic of both diff amp and ADC.


Regards
Vetri

 

[eklikeroomys]

Are you required to physically build an ADC? For high resolution ADCs this can become quite large and difficult as you often require very precise component values to ensure that your ADC will be accurate. If you dont need to physically build the ADC, I would suggest that you requesty free ADC samples from Texas Instruments. They have a wide range of different ADCs (serial/ parallel interface, wide range of resolutions.) If you are using some form of digital control, I would suggest that you use serial interface ADCs, especially if you are going to be using more than one. This is because they use much less pins to your controller. For the diff amp, you can check the link below for a basic description.

Differential amplifier - Wikipedia, the free encyclopedia

 

[vetriselvan]

Hi,
I dont need to physically build the ADC.i need to interface the ADC with micro controller.For that i need help to choose the ADC interface,No.of bits,sampling rates.

I need to connect maximum of 8 channels with ADC.

 

[Thoma HAUC]

Hi Vetri,

Could give us information about the origin of your differential signal (max. frequency, ...)?

Thoma

 

[vetriselvan]

Hi Thoma,
Please find the below attachment for your reference.In that i have used parallel ADC with only one channel..
My requirement is i need to connect max 8 channels from Diff.amp to ADC.So i need help to choose the ADC,interfaces & resolutions.



Vetri

 

[praveen sinha]

u can use microcontroller....it will solve ur problem

 

[vetriselvan]

Ya..i am going to use micro controller next to ADC.But i need help on to select the ADC part no based on interfaces,resolution & sampling rates.Also i need your comments on the above attached schematics.

 

[eklikeroomys]

1. Ok, since you will be using up to 8 ADC channels, it is better to use serial interface ADCs as it will require much less pin connections to your microcontroller.

2. What is the maximum frequency component of the signal that you will be sampling with the ADC? Take this maximum frequency and multiply it by 2. The result that you get is the minimum sampling frequency that you can use to sample the signal. (According to Nyquist's Sampling Theorem)

3. The resolution that you require depends on the accuracy that you require in sampling the signal. The resolution will determine the voltage increments wherein the signal will be digitised. You can calculate this voltage increment by dividing your reference voltage with 2 to the power of N, where N is the resolution of the ADC.

4. I suggest that you read up on the basics of ADC as this will help you make appropriate decisions.

 

[vetriselvan]

yaeh..Ok..thanks for your help.