Webench design in LTSpice issue

[bowman1710]

Hi Guys,

Im trying to simulate this design in LT spice from a webench design. I have already done a low pass filter and it works fine but when i go to use this on LTspice it doesnt run. I think im a bit confused with whether ive wired the Vcm and Vcm1 right, any ideas/ pointers whats wrong with this?

 

[mtwieg]

There is no established bias voltage on the Vcm1 net (the one connected to R18, R24, and R28).

 

[bowman1710]

What do you mean by "established" bias voltage?

 

[amit.kumar11]

Hi,

there is no reference voltage for VCM1 net. Try to provide the ref voltage for that net.

 

[FvM]

What do you mean by "established" bias voltage?

What do you think is the meaning of Vcm1 and Vcm labels in the original Filter Designer schematic? Names for floating circuit nodes? Vcm1 must be obviously connected to a voltage source or a bypassed voltage divider, Vcm at least to a sufficient large bypass capacitor, or shorted to Vcm1.