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THS7350 Power Supply Voltage

Other Parts Discussed in Thread: THS7530

Dear Sir.

I have a question.

According to spec Vs +, Vs-some of the "Vs-to Vs +" in the data sheet of the THS7530.
This specification has been described as a Typical 5V.
Also, all of which are described and VS + = 5V, VS-= 0V is the circuit diagram on the data sheet.
So question is, what can be used as a power supply of ± this? It Will it be the use of a single power supply or?

Best Regards.

Y.hasebe

  • Yoshiki,

    The maximum difference between V+ and V- can be 5.5V.

    This can either be  a single supply with V+ = 5.5V and V- = 0V, or it could be a dual supply with V+ = +2.75V and V- = -2.75V or any combination that meets the maximum 5.5V differential specification.

    The difference between the two voltages (V= and V-) is the the important specification.

    Please let me know if you have any further questions.

    Richard Elmquist

  • Hello Richard-san,

    Thank you for your Information.

    I understand spec of power supply for THS7530.

    So, I have one more question.

    I got information that gain does not change when some customer have been tested with the attached sheet.

    ( V_GAIN is-2V in the circuit of the attached sheet ,but VG + is 0 ~ 0.9V on the data sheet.)

    Please let me know why the gain does not change.

    Best Regards.

    Y.hasebe

    0336.SampleCircuit.pptx

  • Yoshiki.

    I am trying to run a simulation on this, but I am not sure of the values that you are using.

    Could you please send me the values you are using for (+) and (-)? I am not sure from the drawing as to whether these are DC voltages. The (+) input seems to be a AC signal. Is it 1mV pp?

    What are you using for G+? The differential between Vg+ and Vg- can only be 0.9V. I looks as if you are setting this at a higher voltage. This is a differential voltage (max 0.9V) between the two pins.

    Please let me know that values and I will try and simulate what you are seeing.

    Please let me know if you have additional questions.

    Richard Elmquist

  • Hello, Richard-san

    Thank you for your reply.

    Also, I'm sorry is not enough information.

    I answer the questions that I received.

    The following simulation conditions,

    AC Characteristic
    Vg+=-2V(DC) ,  THS7530 reference model don't have Vg- pin.
    Vin=20mVpp(AC) SinWave 10MHz
    I'm sorry to mistake that "1mV"  use for simulation of DC characteristic.
    The following real circuit conditions,
    Vg+=-1.5V~-2.5V(DC) ,  Vg-⇒Currently, confirmation to the customer, I will contact you as soon as I know.
    Vin=20mVpp(AC) SinWave 10MHz
    Output gain does not change even if the variable in -1.5V~-2.5V the value of Vg +.
    TINA reference model of THS7530 do'nt have Vg- pin.
    On the simulation of TINA, what's going on is Vg-?

    First, we will contact you the current information.

    Best Regards,

    Y.Hasebe







  • Hello, Richard-san

    I will send you additional Information.

    I apologize that there was some mistake in the information you sent last time.

    The following real circuit conditions,

    Vs+=2.5V、Vs-=-2.5V
    Vg+=0~0.9V(DC) ,  Vg-⇒GND
    Vin=1mVpp(AC) SinWave 10MHz
    Voffset=0V
    Output gain does not change even if the variable in -1.5V~-2.5V the value of Vg +.
    Best Regards,

    Y.Hasebe
  • Yoshiki,

    With the set-up you described above you should see the gain change in the THS7530 if you vary the Vg+ voltage.

    You did change the differential Vin in the last post to 1mVpp from 20mV, but you should still see a gain.

    Is this a simulation or are you actually using the chip?

    If it is an actual test, do you see this in just one chip or in many?

    I am working on this and will respond back as soon as I have a resolution.

    The simulation does not seem to be providing the proper results.

    Richard Elmquist

  • Hello, Richard-san

    Thank you for your answer and I apologize that I confuse you.

    This is a problem in the use of actual rather than that of the simulation.

    I will answer for your question.
    Is this a simulation or are you actually using the chip?

    ⇒Information of the previous post is the actual use conditions.

    Actual using condition as follows,

    Vin:      ~1mVpp、10MHz SinWave

    Vg+:      0V~0.9V

    Vg-⇒GND

    Voffset:    0V

    If it is an actual test, do you see this in just one chip or in many?

    Currently, I have to confirm to the customer.  

        I will contact you as soon as the information is entered.

    Best Regards.

    Y. Hasebe
  • Yoshiki,

    If the customer is connecting Vg- to the -2.5V rail and applying a voltage of -2.5V to -1.5V to the Vg+ they should be seeing the corresponding gain on the output.

    The factory engineers tested this in the lab. The graph below shows the raw gain comparing the data sheet numbers to the simulation model and actual bench tests using the voltages stated above.

    So the device should function as specified.

    Please let me know if they are seeing this issue on all of their devices.

    Richard Elmquist

  • Hello Richard-san,

    Thank you for your information.

    But I can't see the graph.(I can't open the png file)

    Please resend the graph. 

    Best Regards.

    Y.Hasebe

  • Yoshiki,

    You should be able to see it in the frame.

    I have attached it as a bitmap (.bmp).

    Let me know if you can open it.

    Please let me know if you have any further questions.

    Richard Elmquist

  • Hello Richard-san,

    I can open it.

    Thank you .

    I will ask for confirmation about this data to the customer.

    I want to see it again just in case the conditions of the measurement graph.
    Will you align with the customer's conditions attached Excel file?

    Best Regards,

    Y.Hasebe
     


  • Yoshiki,

    I do not see the attachment. Can you try and attach it again?

    Richard Elmquist

  • Hello Richard-san,

    I'm sorry.

    I will send to change file type(power point).


    1425.THS7530_Setting Data.pptx


    Best Regards,


    Y.Hasebe

  • Yoshiki,

    Vg+ needs to be a negative voltage if Vg- is -2.5V.

    In other words if Vg- is -2.5V, Vg+ must be between -2.5V and -1.5V. It cannot be +2.5V for normal operation. This is the 0.0 to 0.9V differential between the two pins.

    If the customer is using a 1.0mVpp input, it should still work.

    If the customer inputs the proper Vg+ levels, does the gain seem to work properly?

    Please let me know if the part works properly if the voltages stated above are used.

    Please let me know if you have additional questions.

    Richard Elmquist

  • Hello Richard-san

    Thank you for your answer.

    I will send your answer and question to the customer quickly.

    Then I have one question.

    How do you have connections these clamp pins(VCL+,VCL-) in actual use?

    Best Regards,

    Y.Hasebe

  • Yoshiki,

    The Vcl+ and Vcl- are used to limit or "clamp" the output voltage of the device. By inputting a voltage into these pins the output voltages will be limited to within +/- 60mV of the control voltage over temperature. In other words, if the output of the THS7530 was being sent to another device and it was possible for the THS7530 to output a voltage that was beyond the specified input voltage levels of the receiving device, you could use a voltage in the Vcl+ or Vcl- pins to limit the output swing of the THS7530.

    If you do not intend to clamp the output voltage, you should connect VCL+ to VS+ and VCL- to VS-.

    Please let me know if you have any further questions.

    Richard Elmquist