1
\$\begingroup\$

I have this ADC driver circuit:

enter image description here

There is a passive filter downstream of the driver which works as desired. I'm focused here on the active filter. When I run AC analysis on this circuit configured for a differential input I get the desired and identical frequency response at Vout+ and Vout-

enter image description here

However I need single-ended input. I've configured the circuit in LTSpice like this:

enter image description here

Running AC analysis there is a difference in the frequency response between Vout+ and Vout-

enter image description here

How can I modify this circuit to provide the (symmetrical) frequency response I get with differential inputs using a single-ended input?

\$\endgroup\$
6
  • \$\begingroup\$ You should link the data sheet for the differential amplifier. \$\endgroup\$
    – Andy aka
    Dec 17, 2021 at 22:57
  • \$\begingroup\$ The main lowpass is still symmetrical. That higher frequency feature is not related to it. Probably specific to the used amplifier. \$\endgroup\$
    – tobalt
    Dec 18, 2021 at 6:53
  • \$\begingroup\$ You'll probably need to convert your single ended output to a differential one. Something like this. \$\endgroup\$
    – a concerned citizen
    Dec 20, 2021 at 18:36
  • \$\begingroup\$ @aconcernedcitizen isn't the output already differential? \$\endgroup\$
    – davegravy
    Dec 21, 2021 at 19:20
  • \$\begingroup\$ @davegravy You said you need the filter's input to be driven by a single ended output. So if you intend on keeping the filter's differential output then you need to convert your source's output to be able to drive the filter's differential input. \$\endgroup\$
    – a concerned citizen
    Dec 22, 2021 at 7:49

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.