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Hello.I have some problems with the MAX232.In some cases, when I pluga and turn on the system (with contains the max232), the IC will be inoperated and overheat too much.In other cases, the RX will work OK, but TX not work.I don't know wich's the cause of my troubles...I hope help me.Best Regardsfede
Thanks for the information. What type of 1uF capacitors were used, tantalum, ceramic, or other?
Regards,Ronald MichallickLinear Applications
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They are ceramic capacitors.
was the problem solved? I have the same problem. I have MAX232ID and all capacitors installed as described in datasheet. But sometimes (not very often) MAX232 overheats a lot!!! Power cycle usually helps.
It happens when RS232 side is disconnected, but TTL part is connected to MCU.
What can be the cause of the problem?
I've three Maxim MAX232CPE IC having symptoms as described by you in this thread, mainly gets hot on power-up.
I've prototype circuit conforming to reference schematics, but TTL ports connected to uC.
The circuit operates correctly when Ti MAX232, or ST 232BN IC is used instead.
I have exactly the same overheating problem and I explained the problem in detail at the below link.
David suggests connect a 20 ohm resistor to VCC and I applied this. I'm not sure but this solution seems solved the overheating problem.
I might be able to add some more clues to the this issue.
I am having the overheating problem with MAX232EPE's. The circuit they are in has the correct 1uF capacitor orientations with no other connection errors or problems. I know this because substituting the MAX232EPE with a MAX232N works perfectly with no overheating,
I have tried several different MAX232EPE's in the same circuit. Some work fine while no external circuit is connected but as soon as data is applied to Tin1 they overheat. Another worked fine as long as Tout1 was not connected. The circuit only has Tin1/Tout1 and Rin1/Rout1 connected and through all of the testing I have done yesterday and today I've only put data through Tin1/Tout1.
I have a 22 ohm resistor in series with the 5V supply to pin 16 (as suggested in a previous post) but this only prevents the MAX232EPE's from heating quickly - they still overheat but more slowly.
As i have a socket for the MAX232 I am able to swap them in and out of a known good circuit (good with the MAX232N installed that is) so I am definitely comparing apples with apples.
It does seem as though there is something peculiar to the MAX232EPE's which is causing the problem, in my case anyway.
I think I will just stick with using the MAX232N's until somone comes up with a solution for this.
Is TIN2 unconnected?Logic inputs must always be connected to either a valid low and high signal.Connecting TIN2 to the ground or VCC pin is acceptable, but a 1k to 10k series resistor is preferred.
I've just solved my problem with overheat for my case.
I have a breadboard with only Atmega16 and MAX232 installed. All connections were made according to the datasheets and were triple-checked. My power supply was a usb-port. When I tried to do something with rs-232 my MAX232 didn't do anything but overheating.
The solution was to draw power from another source (a laboratory power supply in my case). First I thought that USB does not provide sufficient power, but then I measured voltage between Vcc and GND with the oscilloscope - it was around 4.7 V. No ripple was noticed either.
So, generally, if you don't know what else to do, try to find a way to increase the "quality" of your power supply.
Hope this will help someone, because this post is #1 Google result for "max232 overheat" :)
Do you have both T1IN and T2IN connected to valid logic levels?
T1In was connected to ATMega16, T2In was not connected to anything.
Have you tried to power your MAX232 from USB? Just interesting.
I have the very same problem of overheating... The conections are checked and I´ve made the same conections that the datasheet...
Is there any chance that if some of the signals entering in Din1 o Din2 rises before Vcc is macking some latching in the MAX3232 that I´m using, and then gets overheat?
We have a complete reel with almost 2500 units... and I have tryed almost 20 of it....
Is there same way solve this?
PLEASE, LET ME KNOW...
Hi again Ron...
Here I´ve got the lot written in the reel:
Maybe that helps a little...
and here´s the TOP MARKING of my MAX:
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