Layout for STM32F373 (or similar)

[Harvs]

Has anyone seen a reference design or similar for the STM32F373 (or one of it's siblings) which makes use of the 16bit ADCs?

I'm a bit surprised that for a device that's target is precision measurement/control, ST doesn't have a demo board or the like that does anything analog-ish.

I'm particularly interested in layout to achieve best results from the SDADC at medium speeds.

[rstofer]

There's an evaluation board but it is pretty expensive.  16 bit ADC is used for ECG and some other things:

http://www.st.com/content/st_com/en/products/evaluation-tools/product-evaluation-tools/mcu-eval-tools/stm32-mcu-eval-tools/stm32-mcu-eval-boards/stm32373c-eval.html

[bobaruni]

There is this but it's not really optimised for the SDADC:
http://ebrombaugh.studionebula.com/embedded/stm32f373breakout/index.html

I have had a play with the SDADC on the STM32F373 and it's very noisy, I have not been able to achieve the SNR in single eneded mode in the datasheet but the closest I got was with an external low noise 3.3v reference and setting PGA gain to 1.
One thing to consider with this chip, at least with the 48 pin package is that the 3 SDADC inputs have a very limited analog input MUX that can only go to a few select pins.
Also you need to decide if you are going to use internal or external Vref as I found out the hard way, you can't switch between them in software alone without modifying the circuit.

[Harvs]

Thanks folks, I didn't realise that eval board had the ECG etc. on it.  Having said that, I've gone through their gerbers and I think that board is simply laid out with two main goals:
1. Must be only two layers.
2. Everything must fit.

Thanks for the feedback/tips @bobaruni.  I expected the performance of an on-chip 16-bit ADC to be fairly average (as far as 16bit ADCs go), but as far as price goes it's the cheapest way to get that sort of sample rate in >12bits by quite a long way.

I'll be putting it down on a 4-layer board, so hopefully with a large ground plane, plenty of decoupling and practically no other digital circuitry on board it should be ok.

[ebclr]

This application note have useful information

http://www.st.com/content/ccc/resource/technical/document/application_note/a0/8e/94/50/ae/d2/4b/5e/DM00124123.pdf/files/DM00124123.pdf/jcr:content/translations/en.DM00124123.pdf