16CH ADC SPI module with an ultra-high precision reference

16x 12bit ADC CH at 3MSps with a reference voltage capable of going as low as 1.3μVPP Noise!

What if you need a fast DAQ system capable of sampling up to 16CH at 3Msps? In case of an SPI capable microcontroller or CPU, here’s a solution using MAXIM MAX11131AUI+.

The MAX11131 is a 16CH SAR ADC IC with 70dB SINAD and not more than 1 +/- LSB INL and DNL. By pairing it with a MAX6126, this 42M3 module will give you 12bit of resolution from 0V to 3VDC.

It is worth noting that this implementation requires a dual rail power supply, possibly with a low noise output, at both 5 and 3.3V (with MAX power out 50mW).

By controlling the module via a Raspberry Pi, it is in principle possible to hook up multiple modules so that one can build a pretty large DAQ system with many ADC channels (this is what I’m doing to build a 320CH ADC DAQ at INFN, even thou there I’m integrating everything on one single board by doing a copy and paste of this module on a bigger PCB).

Arduino (Atmega 328P Microcontroller from Atmel (Microchip)) should be able to read multiple modules, but not at 3MSPS since that speed requires a 48MHz clocked bus.

Note: CS (chip select) and EOC (end of Conversion) pins are pulled high with a general purpose 10k resistor, this means that in normal operation ADC is disabled and EOC line pulled at 3.3V. When sampling EOC will be pulled low by the MAX11131 at each end of the conversion cycle.

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