Old thread but anyhow... Pushing the IC beyond it's max supply voltage may not allow the protection circuits to function properly. I'm not saying your parts are authentic, but even the authentic parts will only take so much.
I don't understand why people here will often push parts to or beyond their maximum ratings. I often don't go beyond 80 or 90%. If that doesn't get the job done, move on to the next stronger part.
i don't know about you guys, but national (TI) sends samples.
i have four LM3886 and a LM1765 (1785? 1875? i don't recall) from them.
the IC itself is the cheapest part of the entire amplifier... essentially free. transformer, plugs (in, out, power) caps (if you don't trust the opamp to do common mode rejection) and case are the 100% of the cost. The ICs themselves are literally free.
Maybe because i am in university and they need a university email?
i have four LM3886 and a LM1765 (1785? 1875? i don't recall) from them.
the IC itself is the cheapest part of the entire amplifier... essentially free. transformer, plugs (in, out, power) caps (if you don't trust the opamp to do common mode rejection) and case are the 100% of the cost. The ICs themselves are literally free.
Maybe because i am in university and they need a university email?
Although "buying" samples from National cost me a bit more than using Farnell, I felt the extra security of knowing I had genuine National supplied chips and that was worth the extra cost.
Pity they restrict samples to 5 only.
I would like to buy direct from the manufacturers using their distribution system that they have set up for small quantity samples.
Pity they restrict samples to 5 only.
I would like to buy direct from the manufacturers using their distribution system that they have set up for small quantity samples.
From where did you purchase them? If from aliexpress or dubious sites, might be they are fakes. But can't tell for sure.
You can use a mains bulb tester in line with mains in your amp with these lm3886, see if they sing or not.
I got mine from RS long back and they were genuine and worked well .
You can use a mains bulb tester in line with mains in your amp with these lm3886, see if they sing or not.
I got mine from RS long back and they were genuine and worked well .
Yes it is Aliexpress, 3 batches, but the prices were from several Euro, up to 15Euro per piece. I hoped If anyone can give me measurement pin5 to pin7 from confirmed genuine one or confirmed fake one.
Definitely not, but ... not too sure about your measurement technique.
Are they unmounted, with all their legs free in the air?
Besides, you do NOT use the Ohm scale to measure a chipamp (or any semiconductor), except in very rare occasions; normal is to use the diode scale, and it´s not rated in "ohms" at all.
It´s actually the voltage dropped through a junction when fed a couple mA.
I also suspect the "2 ohm" value,uncomfortably close to what a cheap meter will show across a short.
As I was testing home made PCB, with chip soldered on it, I measured 2 Ohm ( as this is cheap multimeter, yes it is short). When I could not find any error (short) on PCB, I suspected the IC. Soldered on PCB, or not soldered on PCB, all ICs have ~2Ohm (short) between pin 4 and 7.
