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TINA/Spice/buf602: buf602

david sun77114
Expert 2130 points
Part Number: BUF602
Other Parts Discussed in Thread: TINA-TI, , THS4031, THS3491

Tool/software: TINA-TI or Spice Models

Hello, Dear TI expert,

I have a design, it is very similar to the fig 1 in sboa065.  I don't have very clear requirement yet, I guess the gain is around 4. input is 0.5V, the load is 50ohm. the bandwidth is 40Mhz. 

can I use BUF602 and THS4031 replace buf and opamp in the figure 1. 

and made a simulation of the circuit. 

my questions are, 

1, is this design make sense?

2, if I need increase gain to 8 and want 40MHz bandwidth, THS4031 is not good enough, what is the recommendation of the OP AMP.

Appreciate your help.

David Sun

seems PDF attachments not work, only png shows up. 

4452.12db.pdf5706.buf602 and THS4031.pdf

  • 0
    TI__Genius 15975 points
    Hi David,

    To answer your questions:
    1. The BUF602 cannot operate on +/-15V supplies as you have used in TINA-TI. The maximum supply voltage it can operate at is +/-6.3V supply. Also, you would need to be careful of not overdriving the BUF602 input beyond its ABS max rating with the THS4031 output. Other-wise, the design makes sense.
    2. Before I could suggest a suitable replacement to the THS4031, what supply voltage are you planning to operate the replacement part with? Are you planning to stay with +/-15V supplies or flexible with the pre-amp supply voltage? Note that the BUF602 can only operate to maximum supply voltage of +/-6.3V.

    It might also be possible to replace the entire circuit with a single device - THS3491, which is a current feedback amplifier, and should be able to achieve similar performance results as the circuit you have shown. The datasheet is as shown here: www.ti.com/.../ths3491.pdf

    Best Regards,
    Rohit
  • 0 in reply to Rohit Bhat
    Expert 2130 points
    Hi Rohit,

    Thank you very much for a prompt response, the simulation is modified from other TI source, I forgot to change the working voltage, it is +/-5V.
    I cheched THS3491 data sheet, seems it is a very good solution. one step further, if want a low path filter, cut off at 40Mhz, and with a 12db gain.
    implemented by this THS3491. I couldn't find a model in TINA default components list, nor at TI THS3491 webpage. how to get a simulation model of thie chip.

    Best Regards,
    David Sun
  • 0 in reply to Rohit Bhat
    Expert 2130 points
    This resolved my issue