THS3491 test

Update: see also http://www.ke5fx.com/ths3491.htm

Update: phase-noise with Rg=Rf=4k7. 

THS3491 looks like a good op-amp for frequency distribution amplifiers.

I tried it with a slightly modified FDA-design. With 200R feedback/gain-resistors it self-oscillates, but with 1k resistors (976R suggested in datasheet) it is stable. However I see 16dB of gain-peaking!

Using +/-13V3 supply-rails it does drive a 20Vpp sine-wave-ish looking waveform into a 1 MOhm load.

Phase-noise TBD, if and when the gain-peaking is resolved.

Note stylish extra pins on PCB to ground pin1...

  • PCB with exposed-pad under op-amp
  • Input and two outputs populated.
  • Datasheet vs. reality...