I've tried to get a working simulation for the CD4046 but can not seem to get it to work correctly.
If I leave the 'Advanced Properties' of the CD4046 at default, the simulation seems to run just fine, but the generated frequency is wrong. It is possible that my C and R1 values are wrong at this point. But, I don't know what 'Frequency Range' and 'Frequency Offset' are for. If I leave them at default (600k and 1k) the CD4046 seems to oscillate at around 1kHz even though my C and R1 values should place it around 60Hz (my desired frequency).
My signal input is 60Hz. If I change 'Frequency Range' to 60Hz and 'Frequency Offset' to 0Hz, the simulation runs insanely slow. I let it run for around 14 hours overnight and it made it to 8.9 milliseconds and still had not yet shown any data on the oscilloscope.
If anyone can provide some guidance as to how to use the CD4046 in a simulation, I would be very grateful.
Thanks,
Scott
My design is attached.
How to get a working CD4046 simulation?
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- Professional User
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How to get a working CD4046 simulation?
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- CD4046 PLL Test.zip
- Design file
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Re: How to get a working CD4046 simulation?
Hi Scott,
you'll find in attached files a working project based on CD4046 used as freq multiplier.
I also modified yours to make it "working" (not shure result is what you want). Note that scope don't allow correct works if directly connected to shematic, it's why I added buffers to isolate it from the rest of circuit.
I also made a PLL for a FM transmitter that works well and simulate OK, but I can't give you schematic as it was published in my first tech book.
But I have to admit that all projects I made with CD4046 in Proteus don't accept to simulate correctly.
Remy
you'll find in attached files a working project based on CD4046 used as freq multiplier.
I also modified yours to make it "working" (not shure result is what you want). Note that scope don't allow correct works if directly connected to shematic, it's why I added buffers to isolate it from the rest of circuit.
I also made a PLL for a FM transmitter that works well and simulate OK, but I can't give you schematic as it was published in my first tech book.
But I have to admit that all projects I made with CD4046 in Proteus don't accept to simulate correctly.
Remy
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- Professional User
- Posts: 52
- Joined: Tue 2008-04-29 15:43
Re: How to get a working CD4046 simulation?
Hi Remy,
Thanks for the reply. I have downloaded your examples and plan on trying them out today.
I'm curious if you or anyone else has better / more information regarding how to choose the C1 and R1 values for a CD4046. The only info I can find is older data sheets with small graphs on them for choosing cap values instead of a formula that can be used. The charts are so small it is very hard to determine what the component value really should be.
If anyone (hello Labcenter!) has any information regarding what 'Frequency Range' and 'Frequency Offset' are for, please let me know.
Thanks,
Scott
Thanks for the reply. I have downloaded your examples and plan on trying them out today.
I'm curious if you or anyone else has better / more information regarding how to choose the C1 and R1 values for a CD4046. The only info I can find is older data sheets with small graphs on them for choosing cap values instead of a formula that can be used. The charts are so small it is very hard to determine what the component value really should be.
If anyone (hello Labcenter!) has any information regarding what 'Frequency Range' and 'Frequency Offset' are for, please let me know.
Thanks,
Scott
Re: How to get a working CD4046 simulation?
As I can remember, R1 and C1 values are not used for simulation in Isis.
For R1, you can choose a value comprised between 10 kO and 1 MO.
For C1, min value is about 47 pF / 50 pF.
As base start :
For 1 MHz VCO output, you can use [10 kO / 100 pF] (Vdd = 15 V, lower values if Vdd under)
For 100 kHz VCO output, you can use [100 kO / 100 pF]
For 1 kHz VCO output, you can use [1 MO / 1 nF]
I have the datasheet graph in an old RTC paper book, I can scan you if you want.
Hope this help.
For R1, you can choose a value comprised between 10 kO and 1 MO.
For C1, min value is about 47 pF / 50 pF.
As base start :
For 1 MHz VCO output, you can use [10 kO / 100 pF] (Vdd = 15 V, lower values if Vdd under)
For 100 kHz VCO output, you can use [100 kO / 100 pF]
For 1 kHz VCO output, you can use [1 MO / 1 nF]
I have the datasheet graph in an old RTC paper book, I can scan you if you want.
Hope this help.