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CC2340R5: Poor inconsistency for power measurement on CC2340 LaunchPad

Part Number: CC2340R5
Other Parts Discussed in Thread: ENERGYTRACE, UNIFLASH

I am trying to measure the power consumption on CC2340 LaunchPad, but found the result varies by quite a lot on different boards. 

Here's the result by EnergyTrace for 1000ms Adv and connection(parameter controlled by cell phone):

Board# 1000ms Adv Interval After connection
1 273.7uA 461.5uA
2 29.8uA 197.2uA
3 68.3uA 198.6uA
4 161.9uA 340.6uA

The software was exactly the same on the boards and I plug out the board to make sure the EnergyTrace was initialized again before every measurement. I observed the boards but did not find any difference for layout or part numbers.

Has anyone seen a similar issue?

Best regards,

Shuyang

  • Hi Shuyang,

    There should not be anydifference on those.

    Here are some measures you can do to remove the issue.

    1.) Use uniflash and erase all devices to ensure the flash is cleared

    2.) Use 10 pin header to avoid UART to influence connection

    3.) make sure there is the same difference in both

    Can you please have a look if all boards are equipped with PG2 silicon ? 

    Regards,

    Alex

  • Hi Alex,

    I followed your instruction but still sees varied result from different boards. The PG version are all PG2, and the boards have the same tag of "BOM Rev: A" and "2314" which I assume indicate the manufacturer date.

    Could you please find a few CC2340 LaunchPad and see if you can see the same result? Thanks.

    Best regards,

    Shuyang

  • Hi Shuyang, 

    I repeated your measurement with 4 board on my desk. 

    Board# 1000ms Adv Interval After connection
    1 19 µA  100µA
    2 20 µA 117µA
    3 22 µA 119 µA
    4 22µA 112 µA

    This results here seems to be quite similar.

    Can you please explain me how your current measurement is done and what equipment you used ? 

    Regards,

    Alex

  • Alex,

    Thanks for the test results. I have a finding which may be related: if I use the 20 pin connector to connect the launchpad and XDS110, I got the similar result with you and the results were stable among repeated tests. However if I only connect 3V3/GND/Rx, the result was higher and not stable.

    I'm a little confused because it is contrarary to the application note, is there an explanation of this?

    Best regards,

    Shuyang

  • Hi Shuyang, 

    I did not use the 20 pin header for my measurements.

    I directly powered the device with an DC-Power analyzer and waited for some time. 

    Afterwards I performed the measurement and averaged the result over a couple of seconds. I did not connect any other pin.

    I will forward this thread to the hardware team. Maybe they can explain you this issue.

    Regards,

    Alex

  • Hi Shuyang,

    Could you clarify what you mean by RX line? Are you referring to the UART RX?

    Best regards,

    Bun

  • Yes, I connect the UART RX as the application note suggests.

    BR,

    Shuyang

  • Could you share a picture of your setup and connection so I have a better understand of the use case?

    Typically UART RX and TX are used in pairs.

    Best regards,

    Bun

  • Hi Bun,

    I am following this app note to remove all connections except for 3V3, GND and UART RX:

    https://www.ti.com/lit/an/swra478d/swra478d.pdf?ts=1691067969399

  • Hi Shuyang,

    Apologies I missed the part where you mentioned EnergyTrace.

    In order to narrow down the root cause of this issue I have a few questions:

    1. Which software project are you using for this measurement and was there any modifications?

    2. Could you provide an actual picture measurement setup?

    3. Please ensure the LED jumpers are removed.

    4. If you are running BLE, then RX is not needed for EnergyTrace as no commands are needed to make this measurements. Try removing this and see if it resolves the issue.

    Best regards,

    Bun