AMC1311-Q1: Linearity in the 2-2.5 V range

Hi Oscar,

What measurements/data are you looking for?  In the datasheet our electrical characteristics and typical plots are shown for the linear input range.

Thanks.

Hi Ahmad,

I think the sentence in the datasheet "differential output continues to increase with reduced linearity" sounds confusing to the costumer.

What does reduced linearity mean? Can you quantify this ? Are there any data in this regard?

Looking at this plot in the datasheet, the behaviour seems linear until 2.5. Do you have maybe a zoomed in version of this plot for vin between 2 and 2.5 V?

thanks 

Oscar

Hi Oscar,

Nonlinearity refers to how well the output scales with the input.  Ideally the Vout = Vin* Gain, but this isn't exactly the case across the entire input range.  The deviation of the measured output from the expected output is quantified with the Nonlinearity spec.  

The device isn't supposed to be used past the linear range, and we mainly spec within the linear range.

Oscar Liborio said:

Looking at this plot in the datasheet, the behaviour seems linear until 2.5. Do you have maybe a zoomed in version of this plot for vin between 2 and 2.5 V?

The nonlinearity is very small and can't be visually deciphered.  We don't have a zoomed in plot of the non-linear region.

Thanks.

Hi Ahmad,

Is the non-linearity spec also valid for the 2 to 2.5 V input range ?

I honestly don´t think is it possible to see 0.0x linearity change in the graph below, that´s the reason why the costumer is asking for additional data

Thanks,

Oscar

Hi Oscar,

Who is your customer and what is their application?

The spec is only valid from the -0.1 to 2V range.

We do not have data available for the 2V to 2.5V range.  Please tell the customer to use the device in the linear range.

Thanks.

Hi Ahmad,

The costumer is Panasonic and the application is a DCDC HVLV DCDC for Mercedes already in production.

Normally they only use the component up to 2V, but in a special overvoltage case, voltages of up to approx. 2.3V can be present and they need to be able to make a statement about the accuracy of the measured voltage.

Could you please check the lineariy of the gain of the gain at VDD1= 5 V and VDD2 at 3.3V, for T-amb at RT as well as worst case scenario (based on the datsheet this seems to be at -40 C)

The measurement at RT is pretty urgent since they need to communicate this information to Mercedes. The worst-case scenario can wait untli next week.

How long would that take approximately?

Thank you in advance

Oscar

Hi Oscar,

We do not characterize the non-linearity past 2V.  I can check what it would be on a part, but cannot guarantee that the measurement will hold across all units.  If they need high accuracy of their overvoltage case, I would recommend they modify their voltage divider so that the voltage on the input of the device in the special overvoltage case is less than 2V.

Thanks.

Hi Ahmad,

It doesn´t have to be a full characterization, but they need a statement and measurement about the linearity for the condition mentioned above (VDD1= 5 V and VDD2 at 3.3V, for T-amb at RT as well as worst case scenario (based on the datasheet this seems to be at -40 C)) for  2 V < Vin < 2.5 V.

Since the project is already in production they cannot change the voltage divider.

This device is also planned for the next gen of the DCDC converter, so it is important that we can support them here.

When is the earliest date by which you can provide the results of the measurements?

Thanks,

Oscar

Hi Oscar,

I can try and get some results to you next week.

Thanks.

Hi Ahmad,

That works!

Thanks,

Oscar