Problem getting LTSpice to simulate with CD4000.lib

[eTech]

Yes, I use the cd4093B model from Yahoo group. Could you please tell me how to set the negative power supply instead of ground?

Hi

Just change the spiceline attribute values to the supply node names.
VDD 0 <<<<change this
VDD VSS <<<<to this

Make sure supply nodes VDD and VSS exist.

eT

Here's a view of the properties for the CD4093B, The SpiceModel attribute has been changed:

 

[jsduan]

HI i wanna simulate this circuit. and the 4093b is used to produce the delay clock. The clock input the U4C is shown and I change the spice model. However, it still can not work.

 

[eTech]

there is no matching voltage sources..

 

[jsduan]

 

[jsduan]

Here is the circuit I built.

 

[eTech]

Post the .asc file

 

[jsduan]

Thanks for your help

 

[alec_t]

The output of U3 is switching between 0V and 5V rather than between -5V and 5V, so it looks like the model needs further modifications to cope with the dual polarity supply.

 

[jsduan]

Yes. I need to make it to produce between -5 to 5

 

[eTech]

The output of U3 is switching between 0V and 5V rather than between -5V and 5V, so it looks like the model needs further modifications to cope with the dual polarity supply.

The model will produce that if the correct input voltages are used..

 

[jsduan]

So could you please tell me how to solve it. In practical, the chip actually can output a -5 to 5V

 

[alec_t]

Get rid of V3 and label that top node as Vdd.

 

[jsduan]

I tried but the output of U3 is constant which is 0 now

 

[alec_t]

You need to edit each 4093 symbol in your asc file as etech suggested in post #21.
Right-click on the U3 symbol. In the pop-up, change the Spice Model attribute from "VDD 0" to "VDD VSS".

 

[jsduan]

 

[jsduan]

I have changed the attribute but the output of U3 is this

 

[alec_t]

Well it's now switching from 5V to -5V, so the model is working and your circuit must have another problem. Probe each part in turn to locate the section giving rise to the unwanted result.