help in vlsi analog low pass filter design

[fareast]

i need to design a 2nd order analog low pass filter using active lpf.my filter specs are:

fc=400kHz
using butterworth response

i've simulated the lpf circuit but can't get the right lpf graph(bode plot).fyi,i've calculated all the resistors and capacitors according to the given formula but end up with the wrong graph.i've no idea what mistake i've done.can anyone help me in designing the desired lpf?

 

[mists]

see the following picture, it is a 2 order sallen-key butter-worth filter

 

[pixel]

You can easily design butterworth (and other) filters using Nuherz Filter Solutions tool.
Here you can download 20-day trial:
https://www.nuhertz.com/

 

[fareast]

see the following picture, it is a 2 order sallen-key butter-worth filter

thank God,finally i got the right lpf response.im lucky to found you here.really appreciate it.thanks mists.
the circuit that you gave me is a multiple feedback lpf,right?i don't even know that it is one of the sallen-key lpf.