Plot DNL and INL of DA converter across codes

If you do a sweep, and then compute the same expression for DNL, you should see a plot of DNL versus the swept variable - or if you're sweeping over more than one thing, you'll get a family of curves, one for each outer swept variable (with the inner swept variable on the x-axis).

Sorry not to be more specific, but there wasn't a great deal of information in your post (such as which tool you're using - ADE L, XL, Explorer, Assembler, how you're sweeping things, which versions you're using, and what exactly the expression looks like).

Regards,

Andrew.

Hi Andrew,

Sorry for not to be more specific. I use DC sweep of voltage source which is input to ideal AD converter which just generate input code for my DUT : DA converter.

Tools I use : ADE Explorer

For LSB, DNL and INL extraction I use the following expression. I would like to extract separately GAIN, OFFSET and DNL/INL error not to mix them together. I'm just trying to do a linear interpolation of the DAC output curve and from it calculate OFFSET, DNL and INL.

Expressions :

DAC_OUT=VS("/DAC_OUT")        "output of my DAC (voltage or current) used further in the expressions"

LSB=average(deriv(DAC_OUT))

OFFSET=average((DAC_OUT - (xval(DAC_OUT) * LSB)))

Ideal DEC output for calculation of DNL and INL (with OFFSET and GAIN error)

IDEAL=((xval(DAC_OUT) * LSB) + OFFSET)

Absolute end relative (to LSB) DNL error

DNL_abs=(step_DAC_OUT - LSB)

DNL_lsb=((step_DAC_OUT - LSB) / LSB)

Absolute end relative (to LSB) INL error

INL_abs=(DAC_OUT - IDEAL)

INL_lsb=((DAC_OUT - IDEAL) / LSB)

With this expressions I'm able to check the DNL and INL of typical run (which is typically quite good :) Now I would like to run 200 Monte Carlo simulations so I will have 200 waves of DNL and INL with DAC input code on X axis.

I would like to calculate standard deviation for every DAC code across this 200 waves to be able to see for which DAC input code change the DNL is the worst.

I have tried to do this with EvalType (corners, sweeps, all) but i didn't succeed. I'm wondering if I could do it with Ocean script.

Thank you

Adam