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Using CD4000.lib with LTSpice

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Ted Jackson

New Member
Hi,

This post is a suffix to this one:

'Problem getting LTSpice to simulate with CD4000.lib' posted by Doktor Jones:

I'm trying to include CD4000.lib and use its JK Flip-Flop model (CD4027) in LtSpice. However, LTSpice throws up the following warning:

WARNING: Can't resolve .param vdd1=vdd

which points to the first .SUBCKT line of the model:

.SUBCKT CD4027B S J C K R Q QN VDD VGND vdd1={vdd} speed1={speed} tripdt1={tripdt}

Are those braced expressions valid in the .SUBCKT line? I downloaded CD4000.lib from this LT Wiki page titled:

LTspiceIV-library Library Listing Expanded

but it doesn't appear to be quite compatible with LTSpice. Can anyone offer a solution? Thanks.
 

alec_t

Well-Known Member
Most Helpful Member
Welcome to ETO!
You need to have a circuit node labelled 'Vdd' in the schematic if using CD4000_v.lib, or else have a .param directive .
 

crutschow

Well-Known Member
Most Helpful Member
Try adding a power source for the CMOS circuits and add a "Vdd" label to the positive node as below:
upload_2018-4-7_12-1-25.png
 

eTech

Active Member
Hi,

This post is a suffix to this one:

'Problem getting LTSpice to simulate with CD4000.lib' posted by Doktor Jones:

I'm trying to include CD4000.lib and use its JK Flip-Flop model (CD4027) in LtSpice. However, LTSpice throws up the following warning:

WARNING: Can't resolve .param vdd1=vdd

which points to the first .SUBCKT line of the model:

.SUBCKT CD4027B S J C K R Q QN VDD VGND vdd1={vdd} speed1={speed} tripdt1={tripdt}

Are those braced expressions valid in the .SUBCKT line? I downloaded CD4000.lib from this LT Wiki page titled:

LTspiceIV-library Library Listing Expanded

but it doesn't appear to be quite compatible with LTSpice. Can anyone offer a solution? Thanks.
Sound like the symbol is missing parameters needed with the CD4000.lib library file.

Open the symbol and:

1. Add this to the "Spiceline" field:
VDD=5 SPEED=1.0 TRIPDT=5e-9

VDD sets the supply voltage. Change 5 to whatever voltage your circuit uses.

2. Add this to the "Spicemodel" field:
VDD 0

This is for internal use by the library.

You don't need to use a voltage supply node with the CD4000.lib library components.

eT
 
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