It seems chip 5's average power consumption is higher than the others.

Any question you want to ask?

Hi Helic,

Helic Chi said:

Any question you want to ask?

Please check below two points.
1) The LFSS_ERR_01 is really fixed in Rev.B?
2) Is there any other issue (such as production test failure) ?

Thanks and regards,
Koichiro Tashiro

Koichiro Tashiro said:

1) The LFSS_ERR_01 is really fixed in Rev.B?

Could you please help to confirm the abnormal result 1.686, does chips VBAT is larger than Vcc?

Koichiro Tashiro said:

2) Is there any other issue (such as production test failure) ?

Need further confirm the test condition firstly.

Hi Helic,

Helic Chi said:

Could you please help to confirm the abnormal result 1.686, does chips VBAT is larger than Vcc?

Yes. Vcc is off. Only VBAT is supplied from backup capacitor.

Thanks and regards,
Koichiro Tashiro

Hi, Koichiro san

Koichiro Tashiro said:

1) The LFSS_ERR_01 is really fixed in Rev.B?

Fixed.

Koichiro Tashiro said:

2) Is there any other issue (such as production test failure) ?

Need more information of this case.

Could you please show me your test method?

How many chips do you test, and how many chip have this issue?

There may be some measurement errors, such as current meter's resolution, or something else.

Hi Helic,

Helic Chi said:

Could you please show me your test method?

Below is the test setup. VBAT is supplied from 3.0V DC.
Digital Multimeter is connected between the power supply and VBAT.

Then VDD is shut off to emulate the power outage situation.
VBAT current is directly measured by multimeter.

Helic Chi said:

How many chips do you test, and how many chip have this issue?

Four chips are tested and one chip is out of spec. (Please see the table in my 1st post.)
As you can see all chips show higher values than TYP.

BTW, the customer does not put the device into STANDBY in their code.
Instead VDD is shut off manually.
In this case, the VBAT current shown in datasheet is applicable?
If not, what is expected VBAT current under power outage scenario?

Thanks and regards,
Koichiro Tashiro 

Let me check these things.

And run some test.

Not so much high current from my side.

I test it on latest Launchpad, Aug, 2025.

And remove all the jumper on MCU side, I can get a 1.2 uA at 25C in STANDBY0.

Koichiro Tashiro said:

BTW, the customer does not put the device into STANDBY in their code.

I also remove the WFI from code, doesn't impact to consumption.

The most important one:!!!!!!!!

Please try to set low current for LFXT:

If the crystal oscillator quality is poor or the PCB layout is poor, this option may cause the crystal oscillator to fail to start.

Hi Helic,

Helic Chi said:

I test it on latest Launchpad, Aug, 2025.

Was there any differences in production test before the latest devices? The customer uses samples tested in Feb.2025.

Helic Chi said:

And remove all the jumper on MCU side, I can get a 1.2 uA at 25C in STANDBY0.

The customer uses their own boards, not LaunchPad, so it is not possible to remove all jumpers.
Does it matter a lot?

Helic Chi said:

Please try to set low current for LFXT:

They tested with four settings.

Here are results. Lowest shows better result, but there are no differences among Lower, Higher and Highest. Why?

Thanks and regards,
Koichiro Tashiro

Koichiro Tashiro said:

Was there any differences in production test before the latest devices? The customer uses samples tested in Feb.2025.

Just as a reference.

Koichiro Tashiro said:

The customer uses their own boards, not LaunchPad, so it is not possible to remove all jumpers.
Does it matter a lot?

Depending on their hardware, whether there is any other surrounding component that causing more current consumption.

Koichiro Tashiro said:

Here are results. Lowest shows better result, but there are no differences among Lower, Higher and Highest. Why?

Lowest will output lower current for external Osc. This configuration is designed for low power application.

Hi Helic,

Helic Chi said:

Lowest will output lower current for external Osc. This configuration is designed for low power application.

I understood the lowest is the best for power consumption.
My question is why there is no differences among lower, higher and highest.
Is this expected?
I thought the current should be lowest < lower < higher < highest, but results was lowest < lower = higher = highest.

Thanks and regards,
Koichiro Tashiro

Helic Chi said:

Is there any issue that related to this question?

No. It is not directly related to the VBAT current consumption issue.
The customer just warries any other HW issue hidden, for example LFXT drive strength configuration does not work for lower and higher.
I will submit new thread for this item.

Thanks and regards,
Koichiro Tashiro