Just a warning to new project builders that the chips you buy off eBay and other other bargain parts and kit suppliers MAY contain counterfeit parts.
A couple years ago I bought two TDA2040 ICs off some eBay seller (parts shipped from US location). One IC installed in known good circuit. It had a DC rail on the output (yes, I powered the circuit with a current limited PSU to test). Other chip was good. I managed to get the seller to send a replacement that worked. I was suspicious of the chips so they sat around.
I decided to see what would happen if I shorted the outputs with a near rail to rail sine wave on it. Both suspected fakes instantly blew. The "real" one I've had since the mid 90's survived even though I left it shorted for several seconds and repeated the test several times on it.
The good IC is shown on the right. The fake's cover cracked off. I guess they forgo the SOA and thermal protection in the fakes. The pins on the good IC are flattened and messy looking because they were bent down and once soldered for horizontal mount. I don't have a photo of the fake, but the legs on the IC are narrow all the way into the epoxy. The good IC's legs flare out a bit.
A couple years ago I bought two TDA2040 ICs off some eBay seller (parts shipped from US location). One IC installed in known good circuit. It had a DC rail on the output (yes, I powered the circuit with a current limited PSU to test). Other chip was good. I managed to get the seller to send a replacement that worked. I was suspicious of the chips so they sat around.
I decided to see what would happen if I shorted the outputs with a near rail to rail sine wave on it. Both suspected fakes instantly blew. The "real" one I've had since the mid 90's survived even though I left it shorted for several seconds and repeated the test several times on it.
The good IC is shown on the right. The fake's cover cracked off. I guess they forgo the SOA and thermal protection in the fakes. The pins on the good IC are flattened and messy looking because they were bent down and once soldered for horizontal mount. I don't have a photo of the fake, but the legs on the IC are narrow all the way into the epoxy. The good IC's legs flare out a bit.
An externally hosted image should be here but it was not working when we last tested it.
