I have been using the INA219 Adafruit (Clone) Curent/Voltage sensing modules that use the TI INA219 IC. I purchased some SOT23 INA219 chips to include the module design as part of my project PCB. I struggled to get them to work or even seen on the i2c bus. I have noticed that the modules use 219A chips but the ones I got from China were 219B chips. They were just purchased as INA219 ICs.
I have removed the INA219A IC from a working module and replaced it with a INA219B IC but it fails to work.
Looking at the datasheet, I can not see any difference to speak of. I am wondering if they are just defective. I buy a lot of stuff from China and I have only ever had one IC be faulty so I do not want to just assume it is the ICs.
They are in a SOT23 package so not the easiest to work with but I am pretty sure they were soldered correctly. They checked out okay with the meter too. I also mounted some on Breakout boards to breadboard it too but the INA219B failed to be seen on the i2c bus, with and without other devices attached.
Here is the only mention I have found in the datasheet. They are listsed on the right by the IC marking A219 & B219.

Full datasheet
http://www.ti.com/lit/ds/symlink/ina219.pdfI think my next move will have to be to order some INA219As from Digi but I am still a little confused why this does not work.
Thanks for any Advice.