Hello,
We are currently using the BQ25101 in our wearable device and it works really well. Because we are a very small wearable, we use a very small battery and the charging current is 4mA. This is below the Spec for the BQ25101 for its Iout(range). This is currently speced to 10mA, but we spoke with some TI apps engineers in the past and they said it would function down to 4mA if we added an extra low pass filter to the ISET pin. We did this and verified that it works very well for our circuit. We did some lab characterization and found that it even functioned down to 2mA so we have some margin for error!
I am currently looking into the charging circuit for another of our batteries (a larger one) and I would like to use a larger package to be able to prototype the circuit in the lab before designing in. Also, I would like to use a larger package to reduce the cost of the SMT on this larger circuit. The perfect package for me would be gull wing (SOIC maybe?). I did some research on the TI website and found the BQ24090 seems to have the same specs (a little more robust to interface with USB) and comes in a gull wing package.
My questions are:
(1) if we applied the same low pass circuit to the ISET pin, would the BQ24090 operate at 4mA charging current like the BQ25101? I believe this is true based on specs but wanted to confirm with you guys.
(2) Is the charging circuitry functionally the same between these two chips? If not, how close are they?
(3) Do you have any other recommendations for larger package chips that have similar charging functionality to the BQ25101?
Thanks!
Jon