I'm running into some problems designing a 10MHz 8th order sallen-key butterworth lowpass filter.

My requirements are:

- cornerfrequency f_c = 10 MHz
- max passband gain of 0.5dB
- filterorder of 8
- available components: resistors, capacitors, op-amps

What I have tried so far:

I found this TI app-note http://dea.unsj.edu.ar/sredes/sloa088.pdf and tried using the approach from p.16/17/21 of cascading 4 second-order SK stages.

The values calculated are not so practical to begin with but I guess using a different given value for C_1 - C_5 might solve the problem. However simulating the circuit does not give me the expected result:

I also tried using the analog devices filterwizard to aid with the design, but it used an inductance which I can not use:

If somebody could point me in the right direction I would be very grateful as I do not know what I am doing wrong.

Cheers