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OPA569: Design questions about OPA569

Peter Chen(ICP_FAE)
Intellectual 2480 points
Part Number: OPA569

will use 3x OPA569(6A) in 6A Battery application.

here are some questions below:

1)Can Imonitor (pin19) parallel tie together for 6A Max current application.?

2) is there any description about equation IM=ITEC/475 in figure20 of datasheet?

3)in the application scenario, can they tie Thermal Flag(Pin7)in Parallel in this application?

4)in the application scenario, can they tie Current Limit Flag(pin4) in Parallel in this application?

  • 0
    TI__Guru* 93105 points

    Hello Peter,

    Please see my answers to your OPA569 questions.

    1)Can Imonitor (pin19) parallel tie together for 6A Max current application.? The IMON current is a 1:475 copy of the output current. This current is sourced by the IMON pin. Connecting three IMON pins together will result in the sum of three IMON currents. Since the plan is to parallel three, OPA569 together the output current provided by each of the op amps and their IMON current should be approximately equal to each other. 

    2) is there any description about equation IM=ITEC/475 in figure20 of datasheet? The Current Monitor section on datasheet Pg. 13 of the Applications Information discusses this pin function and how it may be used, but doesn't go into how it works inside the OPA569. The Current Limit Accuracy section in the datasheet provides some general information about the internal circuit. I believe that the IMON circuit is a current mirror that reflects 1/475th the current flowing through the particular output transistor sinking, or sourcing output current.

    3)in the application scenario, can they tie Thermal Flag(Pin7)in Parallel in this application? The thermal limit flag is a voltage output function having high and low state voltage levels. If the three thermal flags are connected together they may actually fight each other should one try to move in the opposite state of the other. The pin doesn't have enough current sink/source capability so nothing would be damaged, but the output state may end up at some unexpected level. Besides, it is important to know which one(s) of the parallel amplifiers is going into thermal limit. If all three flags are tied together their individual identity is lost.

    4)in the application scenario, can they tie Current Limit Flag(pin4) in Parallel in this application ? A similar situation exists with this pin function as discussed in question 3.

    Regards, Thomas

    Precision Amplifiers Applications Engineering