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THS3202 EVM

Whitham Reeve
Prodigy 140 points
Other Parts Discussed in Thread: THS3202

I am investigating the HTS3202 for use as a 10.7 MHz IF amplifier in a solar spectrometer (receiver). By a nice coincidence Bruce Carter at TI wrote an article on RF and IF amplifiers that use the THS3202. My question concerns both the THS3202 itself and the EVM.

First, the EVM User Guide says to ground both J6 and J7 for single supply operation. However, J6 is the output of the 2nd amplifier and I think this is a typo. What are the correct procedures to operate the EVM off, say, single supply at 9 to 12 Vdc?

My second question concerns the amplifier itself when operated with a single supply. Does the 10.7 MHz IF amplifier in Bruce Carter's article suffer any performance degradation when operated this way?

  • 0
    TI__Genius 13335 points

    Whitham,

    You are correct, that is a typo. For single supply operation supply ground to J7 and J8, while supplying the positive rail (15V recommended max, but 16.5 Vdc abs max) to J9. This will set the common mode to Vs+/2. For 9Vdc single supply, the common mode will be referenced to 4.5Vdc. This will have a small effect on the amount of peaking in the signal (see figures 1 and 2 of the THS3202 datasheet). The overall performance should be very similar as long as your signal coming in is referenced to new common mode and within the supply limits of the amplifier.

    Regards and happy holidays!

    Luke Lapointe
    High Speed Amplifiers

  • 0 in reply to Luke LaPointe
    Prodigy 140 points

    Luke - Thanks, that all makes sense. The input to my IF amplifier will be transformer coupled from the previous stage to the EVM input at J2..The previous stage is an amplified mixer output.

    One end of the transformer secondary winding normally would be grounded. So that I do not upset the new common mode, would it be advisable to ac (capacitor) couple the winding to the amplifier? I would retain R1 and R2 on the EVM to provide 50 ohm load on the transformer secondary.

    Whit