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OPA541: Could I power supply OPA541 with -80V?

Bill Xu
Intellectual 1110 points
Part Number: OPA541

Hi, Dear PL engineer

one thing need your supporting. I have a customer need TI propose a adjustable ±70V power supply with maximum 5A output current. my idea is to use OPA541 to meet customer requirements. my concerns as below.

1. I believe that I can power supply one OPA541 with a single 80V power supply to get adjustable 5~70V output voltage. Am I right?

2.I also believe that I can power supply another OPA541 with a single -80V power supply to get adjustable -5~-70V output voltage. Am I right too?

3. Could I add capacitor for buffer with series a small resistor? what is maximum capacitor?

4. is there any other issues need I consider? 

thank you so much for supporting!

regards,

Bill

  • 0
    TI__Guru 54996 points

    HI Bill,

    The OPA540 can operate for a supply voltage (V+ – V–) range of 10V to 80V.  The device can be powered with bipolar asymmetrical supplies as long as the total supply is in the range of 10V to 80V. 

    Please consider both the input common-mode limitations of the amplifier and the output swing limitations, these will be delimited by the supplies.

    The input common-mode requires a 6V headroom above and below the V+ and V- supplies.

    The output swing, when the amplifier is loaded with a 5A load requires a 5.5V headroom above and below the V+ and V- supplies.

    For example if you power the amplifier with V- = 0V and V+ = +80V supplies, and configure the amplifier as a unity gain buffer, the input voltage range is delimited to +6V to +74V.  Alternatively, If you power the amplifier with V- = -80V and V+ = 0V,  the input voltage range is delimited to -6V to -74V.

    Please review the TI Precision Las Session explaining "Input and output limitations": 

    https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps.html

    To find the session on , look into "Topics" and browse the bottom of the page, you will find 4-sessions on "Input and Output limitations":

    On question (3), Do you mean the OPA needs to drive a capacitive load?  Is the amplifier configure on buffer configuration? Since this is an operational amplifier, it will need to be compensated to drive the capacitive load. Do you have a diagram of your circuit showing the capacitance range load requirement? We would need to perform a quick stability analysis to compensate the amplifier per the capacitive load (or capacitive load range). If you need additional help please provide a schematic showing the capacitive load range requirements.

    Please also review carefully the OPA540 datasheet requirements regarding the Absolute Maximum Ratings, Current Limit, Safe Operating Area, heat sinking requirements, power-supply bypass capacitors, and PCB Layout Guidelines.

    I also recommend to review the TI Precision Lab series on "Power and Temperature"

     https://www.ti.com/video/series/precision-labs/ti-precision-labs-op-amps.html

    To find the session, look into "Topics" and browse the bottom of the page, you will find 1-video "Power and Temperature".

    Thank you and Regards,

    Luis Chioye