I am designing a digital oscilloscope and i am searching for a 1 or 2 channel12 or 14 bit ADC with 40M sample rate or higher.
Power Dissipation is an important factor because the power will supply from USB and there is another chips in my circuit that will draw current!
can any one guide me for selecting ADC?
can any one guide me for measuring -+50v with differential ADC's?!
I'm waiting .....
Hi, I am definitely not an expert on the subject but I read some article recently that might be interesting for you.
First topic: resolution vs ENOB
Not so High on High-Resolution | Tektronix
Second topic: measuring high voltage and the importance of choosing a proper probe:
Effective Bits: Probe Attenuation - The Overlooked Specification
However given your current requirements I would say that the following ADCs would do the job:
AD9231 Datasheet and Product Info | Analog Devices
AD9248 Datasheet and Product Info | Analog Devices
But you should define your requirements more accurately in term of SNR, ENOB, SINAD to find the most suitable chip.
Hope this could help & good luck!
jbruant, thank you for the information.
BRADDIS, regarding low-power 14-bit dual ADCs, here are two converter candidates in addition to what jbruant suggested:
AD9645 (14bit, dual, 125Msps, serial LVDS outputs)
AD9648 (14bit, dual, 125Msps, parallel outputs)
Regarding measuring +/-50V, you will obviously need to attenuate the signal. Would a passive resistor divider work for you? The parts jbruant and I mentioned are low voltage ADCs, and the amplifiers I am familiar with are likewise relatively low voltage devices.
I'll ask around and let you know if I hear of any ideas for measuring +/-50V.
We have "difference amplifiers" ( http://www.analog.com/en/products/amplifiers/specialty-amplifiers/difference-amplifiers.html#difference-amplifiers ) that have input common mode voltage ranges in the 100s of volts. I'm not sure if these are applicable to your situation.
Please review. If you have questions you can post in that area of EngineerZone, or I can look for the right support person.
thanks for comment's.
I've chosen AD9629 80Ms and I'm working on it!
My new problem is with Mode/OR pin which i don't know what i am suppose to do with this pin...
I don't want to use SPI mode so could i leave this pin unconnected?!
other problem is with supply decouple capacitors..
there is no mention of decouple capacitor but i found 100nf capacitor per supply pins on ad9629 development board's schematic.do you think that is enough?