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OPA549: Can we use OPA549S as current drive with same configuration as LM12C ?

Ankitkumar vyas
Prodigy 10 points
Part Number: OPA549

Tool/software:

Hi Sir / madam,

We have one design with LM12C in which we are replacing the LM12C amplifier with OPA549S.

LM12C is used as current drive, also having configuration of current drive as servo driver, So there are 2 of the LM12C are used as shown in below snap.

 

And

Now, as if we are replacing LM12C with OPA549S, then we have one current limit pin and it is mentioned in the datasheet that the current on I_limit pin varies as per output current. So can we directly replace LM12C with OPA549S with same electrical configurations for Servo drive and current drive ? Or we need to use I_lim as additional feedback input to the feedback path , in place of the feedback from the Series resistor (R6) in output ?

Regards,

Ankit Vyas

  • 0
    TI__Genius 12396 points

    Hi Ankit, 

    This is a full redesign of the PCB, correct? These devices are very different package.

    Electrically, you are correct regarding the standard op amp pin connections (IN-, IN+, OUT, V+, V-). 

    You can still develop the circuit the same way you currently monitor/control the current. Alternatively, you could hard limit the output current using the ILIM pin if desired. 

    ILIM is traditionally connected to the REF pin of the device with a current limiting resistor (method A):

    REF is traditionally set at V- or GND depending on the supply voltage used in the application:

    The last pin (E/S) is used to enable the device, and indicate when the device enters thermal shutdown:

    Please let me know if you have any questions.

    Best,

    Jacob