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CC2640 Calculating Datasheet Current Consumption and Matching Bench Current Consumption.

Ben Malchow1
Intellectual 630 points
Other Parts Discussed in Thread: CC2640

Hi,

We are trying to verify that our CC2640 is consuming the right amount of current.  On the DMM we see roughly 1.98mA and on the power supply we see roughly 2.1mA.

To compare we referred to the table in the datasheet outlining current consumption for each portion of the chip running.

We are using the HostTestApp without power saving.  These are the steps I followed to calculate what the current should be (they do not match our measurements):

+UART (164uA)

+Timers (113uA)

+RF Core (237uA)

+Serial power domain (13uA)

+Peripheral Power Domain (20uA)

+Idle (550uA)

___________

=1.097mA

 

I disregarded the Active current because the application should be in an idle state.

It is imperative that our bench measurements match the datasheet so we have a baseline for our production measurements (Tx/Rx current).  This way we can know if our hardware/software has issues.

Could you possibly tell me what I am missing?

  • 0
    TI__Guru** 106705 points
    HI Ben,

    For current consumption measurements please refer to this application note: www.ti.com/.../swra478

    For static TX and RX current I would recommend using SmartRF Studio to set the device in continuous RF mode.

    To your specific question: What HW are you measuring on?

    Cheers,
    Fredrik
  • 0
    TI__Mastermind 29650 points

    Hi Ben,

    • Did you enable any timers in your code? If not this should not be included
    • The data sheet is missing the GPIO module in the list which is always enabled by TI RTOS (by PIN_init in main)
    • The BLE stack enables the 24MHz XTAL which adds ~200uA I think
    • Which chip revision are you using? Revisions <2.2 have higher current draw in Idle due to a memory bus issue.
    • What have you connected as a host MCU when measuring? Are there any floating input pins?
    • Is the debugger attached when you measure? If so the JTAG and CPU domains will not be turned off in Idle.

    Regards,

    Svend