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Original question:

OPA189: 4channel

OPA189: May OPA189 can output 30V sinewave phase shifter -90degree without distortion?

Chen Bogey8
Mastermind 9990 points
Part Number: OPA189
Other Parts Discussed in Thread: UAF42, OPA551

Hi Sir 

May OPA189 can output 30V sinewave phase shifter -90degree without distortion?

My customer input is single-ended Sinewave 25KHz/15V.

                                                    Bogey

  • 0
    Guru 140200 points

    Hi Chen,

    you mean like this?

    0763.chen.TSC

    Kai

  • 0
    TI__Guru* 93105 points
    Hi Bogey,

    Kai has provided a very nice OPA189 solution. Even though the distortion level produced by the circuit may be very low it will not be distortion free. It would be necessary to measure the distortion and determine if the level produced was sufficient to meet the application requirements.

    Regards, Thomas
    Precision Amplifiers Applications Engineering
  • 0 in reply to Thomas Kuehl
    Mastermind 9990 points
    Hi Thomas

    thanks for your reply.

    Customer have another buffer request as below:
    Input 25KHZ sine wave 24Vpp. Output 30Vpp. Output phase is 0 degree.
    V+15V/V-15V.

    Is there have suggestion part?
    Bogey
  • 0 in reply to Chen Bogey8
    Guru 140200 points
    Hi Chen,

    getting exactly 30Vpp at the output with a +/-15V supply is impossible. No OPAmp can accomplish this. With the OPA189 and a 10k load you will stay up to 110mV away from the rails. Have a look into the datasheet of OPA189 (page 9).

    Kai
  • 0 in reply to Chen Bogey8
    TI__Guru* 93105 points

    Hello Bogey,

    As Kai indicated there isn't any op amp powered by +/-15 V that can provide 30 Vpp output. You would need to power an op amp with +/-18 V supplies, or something close to that depending on the particular op amp's output swing capabilities. The output must remain within its linear operating range if the sine wave is to have low distortion. Any clipping will increase distortion.

    If you want the op amp circuit to generate the 25 kHz sine wave and provide a reasonably accurate 0 and 90 degree outputs, you could apply a UAF42 active filter circuit (there is also a 180 degree phase output as well). You would have to follow the two UAF42 outputs with higher voltage op amp amplifiers obtain the 30 Vpp levels.

    You can find the UAF42 application note here:

    There are higher voltage op amps such as the OPA551, that can easily provide the 30 Vpp output. Its supply voltages would have to be higher than +/-15 V as explained.

    http://www.ti.com/lit/ds/symlink/opa551.pdf

    Regards, Thomas

    Precision Amplifiers Applications Engineering