Part changes current consumption with hand approach or touch

[gaminn]

Hi,
I'm designing low power ADC converter using MAX11210. According to datasheet, their eval board and their technical support I made a minimal setup:

AVDD = DVDD = CS = REFP = 3V3 (supplied by HP E3615A or 3V3 linear regulator supplied by USB port), decoupling cap on both AVDD and DVDD
REFN = AINP = AINN = GND

In this configuration the part should be in low power state consuming max. 4 uA. However I experience huge current fluctuations, mainly when I approach my hand to the part ot when I touch its pins with my finger. The current fluctuates between 0 to 350 uA.

One special case is when I touch DVDD pin with my finger then the part consumes steady 2 uA which is correct sleep current.

I have tested this with 4 chips.

I have never experienced any part to change its Icc when I approach my hand or touch it by finger.

I'm not beginner HW engineer but this time I'm really stuck... Hopefully someone can give an advice.

[wraper]

Most likely you left CMOS inputs floating. http://www.ti.com/lit/an/scba004d/scba004d.pdf

[dmills]

Somethings possibly honking, do you have any open circuit pins on the part?

The proximity thing makes me think it is taking off somewhere up in the VHF, but the other thing that causes excess current consumption is cmos inputs left to float.
The gotcha with this is GPIO pins which if floating should be set to output and driven one way or the other.

Regards, Dan.

[gaminn]

Yes, floating pins... F*ck. I spent two days communicating with Maxim support whether there is a need to use pull ups/downs on some pins, the told NO

The problem was connected with GPIO1 - 4 pins and CLK pin which I don't use. Configuring GPIO pins to output and connecting CLK to GND or 3V3 solves my issue.

Thanks