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TINA/Spice/LMH6619: Why is my simple inverted amplifier circuit not working well at high frequencies?

Part Number: LMH6619
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

 

Hi! I am currently building a simple amplifier, and the TINA-TI simulation results show the above results.

The first one shows the AC Transfer characteristic when the ideal op-amp is used.

And the second one uses the spice model of the LMH6619 op-amp.

When I switched to the real op-amp model, there was a gain increasing portion between 1MHz and 10MHz, but I don't understand what caused this.

However, a 100 Ohm resistor was connected to the output terminal, the gain increasing was disappear.

What causes these problems? Thanks! :)

  • Hi Yong,

    the LMH6619 is a HF-OPAmp and is not designed to work with such high ohmic feedback resistances. When you have a look into the datasheet you will notice that the feedback resistance in all schematics is below 3kOhm.

    Kai