What is the difference between the INA219A and the INA219B - Page 1
Forum section: electronics / beginners

author: castingflame
author_rank: Regular Contributor
timestamp: November 10, 2018, 07:58:21 pm
content: 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 datasheethttp://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.

author: oPossum
author_rank: Super Contributor
timestamp: November 10, 2018, 08:06:33 pm
content: Page 5Offset voltageNote 4

author: castingflame
author_rank: Regular Contributor
timestamp: November 10, 2018, 08:26:08 pm
content: Thanks for your quick reply oPossum.I searched the document but for some reason that was not found. That offset voltage difference would not account for not seeing the IC on the i2c bus. I never got to the point of actually measuring anything with it.I have just looked at the Adafruit Schematic and although my module has a 219A, it is listed on the schematic as a INA219BIDCNT. This maybe because it is a clone, but it is faithful in design.EDIT: Schematic

author: castingflame
author_rank: Regular Contributor
timestamp: November 10, 2018, 08:48:40 pm
content: The Official Adafruit board does have the 219B (B219) so I am even more confused.

author: oPossum
author_rank: Super Contributor
timestamp: November 10, 2018, 08:59:35 pm
content: Probably fake parts.I think it is possible to get the INA219 with a different IIC address, but that is a special order, not a normal production part.You could try running an IIC scanner to see if it responds at a different address.

author: castingflame
author_rank: Regular Contributor
timestamp: November 10, 2018, 09:07:12 pm
content: Yes I used an i2c multi-speed scanner first. The modules come with a default i2c address and two address pins to change the i2c address. I have used these for a while now. A working clone board was seen on a rolling bus scanner, removed, replaced the A219 with a B219 IC and plugged back in. Was just not seen on the bus.I too think that the only thing it can be is faulty/dodgy chips. I checked all voltage levels and SDA, SCL on my scope and it all looked good at the IC pin leg as well as the breakout-board and Module.Guess I will have to pay the expensive Delivery from a vendor like Farnell, Digi or Mouser.

author: blackdog
author_rank: Frequent Contributor
timestamp: November 10, 2018, 09:19:15 pm
content: Hi,Just read the documentationThe "B" version has better offset specifications!Kind regarts,Blackdog

author: oPossum
author_rank: Super Contributor
timestamp: November 11, 2018, 12:04:31 am
content: Quote from: castingflame on November 10, 2018, 09:07:12 pmArrow.com currently has free shipping and they have INA219A in stock.

author: castingflame
author_rank: Regular Contributor
timestamp: November 11, 2018, 11:11:21 am
content: QuoteThanks oPossum, they have never come up in google but I guess that is because i'm in the UK. It is still free shipping though which is great. Thanks for saving me some money!QuoteYes thanks for that!...Searching PDFs normally works fine and I am not sure why, on this occasion, it only found some of the results. ANOTHER lesson learned.Thank you guys, I think this one should sort itself out with new parts. Glad I was not going mad and my suspicions may prove true.

author: castingflame
author_rank: Regular Contributor
timestamp: November 11, 2018, 11:59:01 am
content: Just a quick update. I removed the B219 from a working Clone module and mounted it onto a chip carrier breakout board. Using a breadboard with fly-leads to my PCB confirms that it works so the Chinese ICs must be duff. Well out of thousands of parts from China, it is the first faulty ones I have had. Not bad odds really I guess. When I get to the end of the development of the project I will use all genuine parts for the build from a decent distributors. I can not afford to do that generally though.Thanks again for the help. I'll place an order with Arrow.

author: oPossum
author_rank: Super Contributor
timestamp: November 11, 2018, 03:15:32 pm
content: Quote from: castingflame on November 11, 2018, 11:11:21 amhttp://www.octopart.comhttp://www.findchips.comOften more useful than Google.