OPA1602: OPA1602,OPA1612 burning hot

Hello Hui,

There may be a circuit connection issue with your OPA1602/OPA1612 active filter circuits. 

It appears that the output of OPA1602 U6.2 shorts to the output of U4.2, and the output of U6.1 shorts to the output of U4.1 via a series of 0-Ohm resistor shunts. For Example, R35, R51, R49 is the upper path between the U6.2 and U4.2 outputs. And there is a similar 0-Ohm resistor between the U6.1 and U4.1 outputs.

Op amp outputs are essentially very low impedance voltage sources. If two op amps having there outputs shorted together have different output offset voltage levels (Voso) it is the same as connecting one voltage source across another. Since they are at different voltages one output will try and source as much current as it can to the other output. This can result in maximum output current flowing between them. That high current increases the op amp power dissipation tremendously compared to the quiescent condition. They will self heat excessively.

Check your active filter design and make sure that you do not short op amp outputs together.

Regards, Thomas

Precision Amplifiers Applications Engineering

Hi,Thomas,

actually, R35,R51/ R36 R52 are not welded on this circuit , so the output shorts situation is not exist. 

However, the bruning hot still exist.

Hi Thomas , 

thanks for your reply, i know the reason , the feedback Caps connected at a wrong situation, like C8,C9,C12,C13 etc, 

This filter design based on mutiple feedback topology, 

but,this design the feedback Caps connect before R3 , which is wrong .