K61 Idd_vlpr typical current vs maximum current

[lechlachowicz]

The Idd_vlpr [all peripheral clocks on] is as two values on the datasheet; 2.2mA typical, 38mA maximum.

Note 5 is also referenced.

Why is there a 17X increase in current for the maximum Idd_vlpr value?

What was the configuration of the unit under test when the maximum current was measured or calculated?

Was this maximum current value measured/calculated at 23C, 85C, 105C?

What is the typical and maximum current value at 23C, 85C, 105C?

Lech Lachowicz

[philip_drake]

Hello,

I have worked with the product engineers in the past on other Kinetis devices and found that the disparity between the typical room IDD data and the max IDD can be explained by the condition of the testing. The typical values are characterized at 25C, 3.0 Volts.  The maximum represent the maximum IDD limit of a large sample of silicon at the maximum junction temperature with some extra guardband.  This maximum will never be exceeded if the MCU operating conditions are within temp and voltage specification. 

If the temperature extremes your product will see do not go much above a 70 C (160 F) then the IDD of the device will be much less than the maximum.

If you look at the IDD specs of VLPS and note the Max of the room temp is 1.3 ma and the spec increases to 7.6 ma for 70C.  This is in the same realm of increase seen in the VLPR IDD spec.  

The last thing I would like to mention is that the K61 is a highly integrated MCU with large amounts of FLASH, RAM and many peripherals including DDR, Ethernet and USB.  All of these features become a part of the IDD limits in an all-clock gates on specification.  As you turn off the clocks modules that cannot work at VLPR, USB, Ethernet, DDR controller, etc, and disable the pin controls of large number of unused pins for the same modules the IDD numbers will decrease accordingly.

I hope this helps.

Regards,

Philip

[david_diaz]

Hello,

This kind of tests involve a lot of pieces and therefore a lot of statistical information.

The test was made with the device operational temperature, from -40 C to 85 C, in order to get the following information:

• 2.2mA typical
• 38mA maximum

Unfortunately it is difficult to know exactly the typical and maximum current value at random temperature.

Factors such as ambient temperature and pressure, provoke that silicon reacts differently.

Provided that it is not exceed the operating temperature, the MCU will respond typically. 

Hope this information will be useful for you.

Have a great day.

Best Regards,

David Diaz.