[moved] Microcontroller Current Consumption when different internal and external clock modules are used simultaneously

I am using this Microcontroller - S32K142 64 pin.

From the Figure 4 in this Application Note, We can see there are 4 clock sources for the Microcontroller.

FIRC - 48MHz

SIRC - 8MHz

SOSC - 4-40MHz

LPO - 128kHz

SPLL - 112MHz

From the clocking tree diagram, Figure 4 in the application note attached, I can see that the core clock frequency of the Microcontroller can be derived from any one of the sources like FIRC, SIRC or SOSC and can be upconverted with the help of the SPLL.

My questions :

1. What is the maximum core clock frequency that the microcontroller SPLL can provide? Is it the 112MHz from the SPLL?
2. Objective is to calculate the current consumption due to different peripherals (Like I2C, SPI etc) and their clock module sources (like if I am using FIRC, SIRC and SPLL simultaneously)

Regarding current consumption - Suppose I use the 112MHz as the core clock frequency of the microcontroller i.e.HSRUN mode, from Table 13 of the datasheet,I get that, at 25degC, the current due to the oscillator is 112*360uA = 40.32mA? Isn't this a very high value? Am I correct in calculating the oscillator current, this way?

So, If I enable all the peripherals in HSRUN mode, my total microcontroller current consumption would be 52.2mA+40.32mA = 92.52mA. Is this correct?

But I am confused like, what about the current consumption due to FIRC & SIRC usage(suppose if I use FIRC & SIRC clock source also)? Suppose, I also use the FIRC module for some other peripherals, say like SPI at 48MHz. What would be the current consumption due to the FIRC module usage? Would it be 48*360uA = 17.28mA? And I use the SIRC for I2C Interface (downconverting the 8MHz SIRC to 400kHz). How to calculate the current consumption due to SIRC source?

(The 40.32mA current was only due to the HSRUN mode which derived its frequency from a external resonator of 8MHz and upconverted to 112MHz by the SPLL). So, should I add the currents as I am using 3 different clock sources (FIRC, SIRC and SPLL)?

Please help to clarify - to calculate the current consumption due to different clock source (FIRC,SIRC and SPLL) module usage and peripheral module usages?

Yeah, that data sheet is really confusing. It's not clear if the right-hand column is TOTAL current, or if it's added to the appropriate columns from the left. If you look at note 4 it says :

Values mentioned for S32K14x devices are measured at RUN@80 MHz with peripherals disabled

Which leads me to believe that it's total current. But I'd just contact the manufacturer for clarification.

barry said:

Yeah, that data sheet is really confusing. It's not clear if the right-hand column is TOTAL current, or if it's added to the appropriate columns from the left. If you look at note 4 it says :

Values mentioned for S32K14x devices are measured at RUN@80 MHz with peripherals disabled

Which leads me to believe that it's total current. But I'd just contact the manufacturer for clarification.

Click to expand...

Thank you for the answer. But, In general, - If in a microcontroller, we use different internal clock sources (say like 48MHz and 80MHz), we need to calculate the current due to the individual current sources, right? Or how is it done? (Let us assume that the 48MHz is from the external resonator and the 80MHz is done with an internal clock source of 8MHz and increased with a PLL)

Sure, if the manufacturer gives you enough information you can calculate power consumption based on clock speed. But I don't think they (generally) break it down that way with a current/Hz parameter like FPGA manufacturers do. The device you've chosen actually DOES give you that information, so, use it.