Max232cpe heating up

I’m using the max232cpe to go between ttl and rs232 and have wired it as https://www.maximintegrated.com/en/products/interface/transceivers/MAX232.html does.

It heats up when I connect voltage to it, and also, as the RS-232 is connected to a PC via an aten USB to RS232, when I hook up voltage to the chip, the aten converter lights up as if data is flowing. Without power, the chip manages to get data from the Arduino altsoftserial to the PC, but not the other way. Also, with power, the chip starts heating up considerably.

Hi,
Is this your circuit?
1798

What voltage do you measure between gnd and pin 2 and gnd and pin 6?

Can you post a picture of your project so we can see your component layout?

Thanks… Tom… :grinning: :+1: :coffee: :australia:

Some of the max232 I’ve bought off eBay have randomly got hot and destroyed themselves . I now only buy these from the likes of RS components and not had any issue .

Having said it is is worth checking you have the connections to the capacitors correct ( one in particular ( C4) has its positive connection to 0v which can confuse ) , you also need a capacitor across the power supply .

1 Like

1.6V between pin 2 and 6.

max232 setup

It’s not easy to see in the pic since I don’t have short jumper wires.

I’ve also tried using 1µF caps as well as 100nF caps. I’ve also tried grounding the other end of C3 from that maximintegrated sites since I’ve seen other people do it. No matter what, I get one way operation working well without extra power.

I did buy these off of eBay. I’ve recently ordered some from Jameco since I had a feeling that could be an issue.

I did put a cap in the power supply since I’ve had that as an issue with other circuits.

I also tried changing power supplies. At first I used the 5v from the Arduino and then from a bench supply. It still over heats.

As for cap 4, I’ve put its positive end to ground.

I have built rs232 interfaces for arduinos on custom pcbs from chips of ebay a few times with no problems. I d be scared to set this up on breadboard however . its so easy to get the wiring wrong. In addition, the the effect if long jumper wires for some of the connections could be problematic. I would just buy a ready made rs232 module instead.

It is part of a larger system that I’m designing, so ready made isn’t exactly on the table. Thankfully I found some max232 chips from mouser, and they don’t overheat, and I’ve gotten data to go across them, so I can consider this case closed. I guess I won’t get chips like that from China from eBay anymore.

Do you mind sharing the eBay seller where you got those chips so that we don’t make the same mistake?

Sure thing: longshen-electronic.

Thanks!
I buy chips from an ebay seller called alice1101983. Also from China but no problems so far.

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