MAX3243: MAX3243 IC

Hi Clemens,

Thanks for your reply.

But IC is getting failure after 3~6 months.

How often is this connection (un)plugged? I'd guess there is not enough ESD/overvoltage protection.

Hi Clemens,

Once the unit is ON Conditions, the pin gets 12V.

Unit will operate for 24x7

Hi Siba,

Are you plugging/removing a cable from the RS232 port often? 

You may want to probe the pin to verify if the voltage is seeing 12V or if the cable plugging/unplugging is causing the voltage to exceed the max rating.

-Bobby

Hi Bobby,

Thanks for your reply.

Once connected RS232 cable, it will not be unplugged.

Any issues whether the 12V supply from SMPS is directly connected to Rin - Pin4 (RS3243 IC).

Thanks,

Siba

Hi Siba,

The absolute max rating for the receiver pins are +/-25V so 12V should not break the device. Cabling does have inductance on it which during a live plug event could temporarily exceed that threshold. From the sounds of it, damage that breaks the part over a few month time frame may be some kind of reoccurring transient. 

For the damaged devices, do you know what pin is no longer working or the failure signature? (like you now see a short between two pins? or the Rout pin no longer outputs high?)

-Bobby

Hi Bobby,

Thanks for your support.

Fault IC image is enclosed for your reference.

No Pins are shorted to GND

Thanks,

Siba

Hi Booby,

Fault IC image is enclosed for your reference.

No Pins are shorted to GND

We connected 12V to Pin4 - RIN4 (Connected to CTS PIN of Serial Port Header), Now there is No RS232 communication between two devices due to this failure.

Thanks,

Siba

Hi Siba,

I can't see what you uploaded. 

Siba Murugan said:

We connected 12V to Pin4 - RIN4 (Connected to CTS PIN of Serial Port Header), Now there is No RS232 communication between two devices due to this failure.

This is also very vague. No RS232 communication can mean a lot of different things. 

If you connect the DIN pins to a square wave generator, do the DOUT pins output to the correct voltage and mirror the square wave?

Are the V+/V- pins regulating to the correct output voltages?

-Bobby

Hi Bobby,

Thanks for your support.

Reference schematic enclosed.

From SMPS 12V supplied to Mother Board, from Mother Board 12V supply is connected to serial port header Pin8 - CTS and same connected to PIN4 - RIN1 of MAX3243.

PIN4 - RIN1 is got damaged, so no communication between Mother Board and External pheripheral.

We need to know if 12V is applied continuously to PIN4 - RIN1 of MAX3243 whether IC will get damage?, if so please let us know.

Thanks,

Siba

Hi Siba,

The top marking shows the device was made from December of 2022 and I was able to find it in our system. 

I checked the schematic, I don't see an issue (I'm assuming the note below the IC that states pins are not actually floating is correct).

Siba Murugan said:

We need to know if 12V is applied continuously to PIN4 - RIN1 of MAX3243 whether IC will get damage?, if so please let us know.

Again. the device is rated up to 25V on the RS-232 receiver pins as the absolute max value it can support. I don't think this is where the damage is coming from unless the 12V signal somehow shoots above 25V. 

Siba Murugan said:

PIN4 - RIN1 is got damaged, so no communication between Mother Board and External pheripheral.

What is the damage signature? (How do you know this pin is damaged?)

Are there any specific tests you've run on this pin? (Is it shorted to GND/VCC/adjacent pin?)

Did you perform a curve trace and find it doesn't match the other pins or a correlation unit?

-Bobby