TLC393 Op-amp

Hi Deepak,

I don't initially see anything wrong with your circuit, although the large resistor values may cause issues with response time. Could you describe how the part is being damaged? What I mean is are these failures visible (gets hot, smoke, etc) which would suggest excessive power dissipation or does the part just not function properly after a short period? Is the part installed on a pcb or a breadboard? It would also be sure to double check that the part is installed with the proper orientation, for example if the part is rotated 180 degrees it would definitely cause failures.

John,

After 2-3 minutes op-amp gets damaged with with smoke coming out of it. I tested it with 3 op-amps, all damaged like same.

I am using breadboard for placing op-amp. i have tested circuit many times, no shorting b/w pins & no problem found.

Deepak,

Are you using different power sources for 15V and 3V ? Are you switching them on-off at the same time ? Are you ensuring that both 15V and 3V supplies are at 0V while inserting the comparators ?

If the dV/dt is too high, the part can possibly go into SCR latchup and eventually destroy itself. Otherwise it could be an ESD issue. Can't say for sure !

Let's see what TI's experts have to say...

Regards,

JayantD

1. I am using single power supply of 15V & using voltage regulator for 3V. So both are turned off/on at same time.

2. Yes power supply is turned on after proper connections.

3. I have tested on 4 TLC393IP, all bursted from inside same way.

Deepak,

The failures could be due to the effect of some other components in your circuit, which you have not shown in your attached pdf. It would help if you could post the complete schematic. Do you have decoupling capacitors on the power supplies ? Are you sure the 15V supply is clean, without any spikes?

If the ground connection of a linear regulator floats, it's output equals the (unregulated) input. In such a case I would expect circuit behaviour as described by you.

Please do a double-check and revert.

Regards,

JayantD

Jayant,

I have checked it. I don't see any problem in the ckt. I don't understand why this is happening?

Deepak,

I hope the parts are genuine !

Regards,

JayantD

I sourced it from TIeStore.

Any comments/suggestions from TI's experts.

Deepak,

If you sampled the parts from us there should be no issues with them being genuine, and I see no issues with your schematic if it is indeed wired as you show. One method I recommend to help the debugging process is to put a resistor in series with the VDD pin (pin 8) on the part. That way any excess current draw by the part will be limited by this resistor and prevent the part from failing until we can track down the cause of these failures. If possible, could you take a picture of the circuit on your breadboard and post it here?

John,

I have checked same ckt but with LM339. It is working fine. But it has larger power ratings. I will check again on TLC with 10K resistor on VDD.

What could be the probable reason for that.

Regards

Deepak