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igipit

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Hello people.
Doing some experiments (battery discharge curvers) I damaged my DNA200 configures with 2s LiIon .

Now the board displays the "CHECK BATTERY" and the battery is shown totally empty (batteries are OK). Connecting the board via USB to escribe , cell #1 is recognised  but cell #2 has zero voltage, while #3 (not installed) shows a value floating around 1.58V.
The battery pack shows about 5.5 V.

I presume that the battery management chip, the Texas Instruments BQ76925 placed near the USB port, is damaged because it provides the cell voltage measurement analog front end to the SAM D21 ADC. Following the pcb traces I made sure that cell voltages arrive at the BQ76925  pins.

 
The BQ76925 is a 2$ chip, so that i've no problem to try the substitution because it is a SMD with exposed pins suitable for manual soldering.
But here is the problem: the Texas Instrument BQ76925  does not officially  exist with exposed pins. The TI catalog contains two version of the chip a TSSOP-20 and a VQFN-24 but not a Quad with 4x6 exposed pins.

Thus, my questions are 
1) Can you solve the mistery of the existing non existing BQ76925 ? 
2) any suggestion to work around?


Thank you.


VapingBad

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Reply with quote  #2 
Evolv would probably change it under warranty, open a ticket and ask here http://helpdesk.evolvapor.com/index.php?a=add
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• I am not employed by nor do I represent Evolv Inc.  All opinions are my own, they are just opinion not fact and can be wrong •

Latest versions of EScribe: DNA 200/250DNA 75
Common problems
ChunkyButt200

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Reply with quote  #3 
Quote:
Originally Posted by igipit

Hello people.
Doing some experiments (battery discharge curvers) I damaged my DNA200 configures with 2s LiIon .

Now the board displays the "CHECK BATTERY" and the battery is shown totally empty (batteries are OK). Connecting the board via USB to escribe , cell #1 is recognised  but cell #2 has zero voltage, while #3 (not installed) shows a value floating around 1.58V.
The battery pack shows about 5.5 V.

I presume that the battery management chip, the Texas Instruments BQ76925 placed near the USB port, is damaged because it provides the cell voltage measurement analog front end to the SAM D21 ADC. Following the pcb traces I made sure that cell voltages arrive at the BQ76925  pins.

 
The BQ76925 is a 2$ chip, so that i've no problem to try the substitution because it is a SMD with exposed pins suitable for manual soldering.
But here is the problem: the Texas Instrument BQ76925  does not officially  exist with exposed pins. The TI catalog contains two version of the chip a TSSOP-20 and a VQFN-24 but not a Quad with 4x6 exposed pins.

Thus, my questions are 
1) Can you solve the mistery of the existing non existing BQ76925 ? 
2) any suggestion to work around?


Thank you.


you'll never get the analog front end off without some sort of reflow station. i also doubt you'll be able to re solder the chip back on with manual soldering. you might be able to de-solder the pinouts but you'll get to the exposed pad underneath the ic. 

take vapingbad's suggestion and open a ticket with evolv. why not get a whole new board out of the deal?

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• I am not employed by nor do I represent Evolv Inc.  All opinions are my own, they are just opinion not fact and can be wrong •
Latest versions of EScribe: DNA 200 • DNA 75  Common problems
EVOLV HELP DESK - https://helpdesk.evolvapor.com/?a=add
LOST VAPE WARRANTY REPAIR - http://www.lostvaperepaircenter.com
igipit

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Reply with quote  #4 
@VapingBad & @Chunkybutt200: thank you for the advices, I agree with you.

@Chunkybutt200: you are right if the "DNA200 BQ76925" version has an exposed pad, bud  I never saw a 4x6 Quad chip with exposed pad.
jurdanas

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Reply with quote  #5 
"igipit"

Texas Instruments BQ76925, package - VQFN (24 pins).
BQ76925RGER
BQ76925RGET


http://www.ti.com/lit/ds/symlink/bq76925.pdf
http://eu.mouser.com/ProductDetail/Texas-Instruments/BQ76925RGET/?qs=sGAEpiMZZMsfD%252bbMpEGFJUUsTylLh1cc8TRoVyUpQEk%3d
http://eu.mouser.com/ProductDetail/Texas-Instruments/BQ76925RGER/?qs=sGAEpiMZZMsfD%252bbMpEGFJUUsTylLh1cc8GP8fJeDLsw%3d

Maybe helps.
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