So, as part of my VFD project, I’ve been purchasing various ICs from eBay (almost always from China, because they are always the cheapest!)
I’m used to counterfeit ICs turning up from time to time, but I’ve run into the same counterfeit IC (with the same ‘batch number’), and the same problem from a couple of eBay suppliers, so I thought I’d share the issue here.
The IC is a SN74HC595N – a fairly simple 74 series shift register, in a 16-pin DIP form factor.
However, it doesn’t work as advertised.
It’s labelled SN74HC595N, with a batch number of GM1807FSF E4. It is allegedly from TI, but I very much doubt it.
It was keenly priced, at around 5p per IC for a batch of 500 chips.
It is indeed a shift register, but instead of having the tri-state outputs it should have, it seems to have open-collector outputs, like a 74HC596. So it is not usable in my application.
I did find that I’m not the only person having this problem – https://translate.google.com/translate?hl=en&sl=de&u=https://www.mikrocontroller.net/topic/463936&prev=search
One of the sellers has refunded me without too much debate, but I’m still arguing with the other…