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Inquiry Stability of OP200A and OP470A under Incorrect power supply conditions.


The two parts(OP200A, OP470) has been used in satellite system.

The power supplied to the two parts within our design are +15VDC(+V pin) and -15VDC(-V pin) at power-on state.
But, Due to some design error of the main power unit , in case of main power off state, +5VDC power are always supplying at -V pin of two part(OP200A, OP470A) instead of power-off and maintain that state that be remained +5VDC at -V pin.
Of course, when power-off, +15VDC at +V pin is normally power-off and remain it.
An important thing is the error state has maintained to two parts for a long time.

My question is, I'll wish to know, in this case, whether or not affect the stability of the two parts assembled(OP200A, OP470A).

I'm waiting your answer.

Best Regard!

Schematics is attached below.

  • Hello gimkan1, 

    If I understand correctly, you are seeing 5V at the -Vs pin during shutdown. Is this a voltage that you are actually measuring on the circuit? What circuitry is generating the 5V supply? 

    I'll need to take a closer look at this. I will get back to you shortly. 



  • Hello krisf.

    You are right.

    During power shutdown(meaning the shutdown of main power system), +5V is supplying at -Vs pin of OP200A and OP470A.

    Yes. I measured +5V between GND and -Vs pin on circuit.

    The +5V is generated by main power system within satellite.(It means that there is some fault of design at main power system used within satellite. We found it out too late.)