Ebay ACS712-05 modules

[Sparc]

I got a few ACS712-05 current sense modules off ebay to play with.  I found the output voltage does not change with input current in the expected way.  ACS712 datasheet states output should have a sensitivity of 185mV/A.  I measured 132mV/A.   Rise time should be 3.5us for ACS712.  I measured 50us.  Very slow.

Thinking something was wrong, I searched digikey.  Seems there was a ACS704-05 and ACS706-05 parts that did have a 133mV/A sensitivity.   The pinout is also slightly different between 712 and 704/706.   712 has a filter function on pin 6.   On ACS704/706 pin 6 is  connected internally to pin 7.  I removed the filter cap and found that pins 6 and 7 were connected internally inside the IC.  I got a magnifier and looked at the IC.  It has a rough look to it.  Like, maybe it had been sanded and repainted...  Geez.  It looks like someone found obsolete parts and relabeled them or is producing an old design and labeling them as ACS712.  Should this be surprising?  If they were the older ACS704/706, why not just sell them as that?  The circuit board doesn't even match the chip.  More crap from china.

[Simon]

Yes you got done, what you expect eBay and China that's called being screwed to the square. (And I am an eBay seller myself) the part number looks to me like an Allegro part and to be honest their datasheets are at best a whimsical promise of specifications. Buying from eBay in China something like that does not sound like a good idea to me. In the past I've been recommending Lima sensors these are apparently very good.