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ADA4870 in parallel connection. Protection features


I use multiple chips in parallel connection. "ON" pins  I unite through the 1n4148 diodes as shown in the figure.

Protection will work correctly in such shematic? Value of capacitors C1, C2 and C3 affects the  protection speed or not?


I ask these questions because i do not quite understand the internal structure of the chip, and what happens with the voltage on the ON pin when short-circuit occur.


Thanks a lot!

  • Hi,

    My apologies. I'll be contacting our product expert regarding this question and get back to you as soon as possible.



  • Hi Michael,

    Using the factory default value(0.001uF) for the bypass caps between ON bar pin and VEE would give the best performance.

    The attached circuit looks fine if and only if the two ADA4870 operate simultaneously, meaning both amplifiers will detect the short-circuit at the same time and disabled at the same time. 

    It won't work in the case if only one amp detects the short circuit and disables while the rest need to remain on. When the short circuit condition is detect, the amplifier is disabled and will change the ON bar voltage, It will fight with the other ON bars which are still floating. To avoid the false trigger, I would recommend to control the ON bar separately.