Following are my requirements
I have three Accelerometers ADXL203 whose data I wish to convert using a single ADC. The accelerometer is operating at 5V. I am not able to find an ADC with 6 channels and Vref support upto 5V except AD7689. Can any one help me find any other ADCs that can do the following specification for conversion.
1. Greater than or equal to 16Bits
2. Single Ended Vref 5V
3. 6 Channels minimum
4. Minimum 10KSPS for each channel
5. SPI Interface
Just to make sure I don't exclude any potential candidate products can you please comment on the following?
1) What is driving your desire for a solution with 16 or greater bits of resolution?
The ADXL203 has a fairly high noise spectral density and will likely dominate the overall system noise. Are you planning to use significant oversampling to improve the ENOB or is ENOB not really important and you have a requirement for a 16 + bit output? I assume linearity is also important.
2) Would you consider using a simultaneous sampling ADC? From what I can deduce from your query it seems as if you have explored multiplexed solutions.
3) Do you have any restrictions in terms of size, power, cost that should additionally be considered?
Thank you Sean for you quick reply.
1. I wish to use ADXL203 (5G) and two ADXL1001(100g) whose voltage output will be converted with an ADC approximately 10 meters away. There isn't any resolution requirements currently so I am going for 16bits randomly so as to not sample with very low resolution and also not go above 16 bits. Linearity is of utmost importance.
2. I want to use simultaneous sampling adcs but for single ended analog inputs from the above accelerometers operating at 5V, I couldn't find any chips with Vref 5V. (I am not sure how to operate with Vref which do not support 5V Vref when my inputs is 0V to 5V.)
3. I do not have any of the above restrictions, but I wish to sample all the 6 channels at 1KSPS Minimum and sensor operation from DC to 250Hz.
I would suggest taking a look at the AD7761, Octal, 16-bit Sigma Delta ADC. I think you'll find this ADC will provide a solid foundation upon which you can build your solution.