BQ2980EVM-883: Leakage current discrepancy bq298000 vs bq298010

Hey Kevin,

I'm getting in touch with one of our designers to answer your question.

Thanks,
Caleb

Hey Kevin,

The internal pullup is only enabled if the device is configured for PTC mode. Currently none of our devices have it enabled. 

Regarding the high consumption current, have you tried replacing the IC with another one to see if the problem resolves? Make sure that you are within OVP and UVP specs of the new device. If the device is trying to drive a gate to close then it will consume more current.

Thanks,
Caleb

Hi Caleb,

I have replaced the IC with different bq298010's and I still get 100uA's @ 3.8V. Do I need to do anything to modify the EVAL circuit to achieve low current consumption?

Best,

Kevin

Hi Kevin,

Something seems very wrong - the current for this device should never be in the 100s of microamps under any conditions. Are you sure there are no other changes to to EVM? Are you able to replace the original BQ298000 device to see if the behavior is still showing?

Regards,

Matt

Hi Matt,

So I basically grounded CTR on the eval board and checked bq298000 and I got few uAs in normal mode. Once I replace it with bq298010, its in the 100's of uA. Is this something you can check on your end?

This is the circuit I am testing

Best,

Kevin

Hi Kevin,

I cannot check this easily - it would take some time to order samples of the 10 version, and it would be a few days before I could get to this. Every unit is tested for supply current in production test and is characterized under all of the datasheet conditions. Can you give more details about your setup - are you using a power supply or a battery cell? What are you measuring on the CHG and DSG pins and across PACK+/PACK-? With the board unpowered, can you measure the resistances shown in the EVM Guide troubleshooting section?

Matt

Hi Matt,

I am using a power supply to measure leakage current that can sink and source. I went through the table you shared the other day.

What are you measuring on the CHG and DSG pins and across PACK+/PACK-?

CHG Gate = 10.14V

DSG Gate = 9.95

BAT+/- = 3.8000

PACK+/- = 3.8004

If there is anyway you could go through this process... it would really help. Weve been on this issue for a while, and we are trying to start making battery protection systems as soon as possible. This is the last item holding us up.

Maybe the part is getting damaged during rework...There isnt much more I can check on my side..

(UPDATE)-Confirmed that even at lower reflow temperatures I am still seeing the issue.

Best,

Kevin

Hi Kevin,

I can see if someone on our team can look at this, but it will be after the 4th of July holiday. The reason I was asking for the measurements was to verify that something else on the board is not damaged since you have tried multiple ICs.

Matt

Hi Matt,

That would be amazing if you could. The measurement process makes sense. We can wait until after 4th of july holiday, is it possible to order -010 parts now so they arrive next week to validate this issue?

Best,

Kevin

Hi Kevin,

So just to verify: the -00 version has been put back onto the board (after the behavior has been observed on the -10 version) to verify there is nothing else damaged on the board?

Thanks,

Matt

Hi Matt,

Correct. I only see the high current leakage with the -10 version in place of the -00.

Best,

Kevin

Hi Kevin,

We've ordered samples, but it may be a few days before they arrive. I do not expect to see a high current on the -10 variant, but I can check once we receive parts. This variant was characterized and showed similar supply current (and of course this parameter is tested in production).

Best regards,

Matt

Hi Matt,

Have you received the parts / been able to test this on your end?

Best,

Kevin

Hey Kevin,

Matt is out of office till next week. Samples have not arrived yet. I will check back tomorrow.

Thanks,
Caleb

Hey Kevin, the samples have arrived. 

Matt is out of the office for the week so my bandwidth is pretty limited. I'll get to testing as soon as I can.

Thanks,
Caleb

Hi Caleb,

Any status on this?

Best,

Kevin

Hey Kevin,

This week has been pretty hectic for us. I haven't had time to go into the lab. I will work on this issue on Monday.

Thanks,
Caleb

Hey Kevin,

I was able to test out the current consumption for the 010 spin on a 000 evm. 

Current consumption comes back normal at around ~5uA. 

Have you tried another EVM board?

Thanks,
Caleb

Hi Caleb,

This is great news. Can you confirm if you made any other modifications to the EVM? On my side, I grounded CTR to ensure there was no FET override.

Best,

Kevin

Hey Kevin,

CTR was grounded on my test too. That's the only other change I made.

Thanks,
Caleb