Mixed-signal model of CD4093

Is there a mixed-signal model of the CD4093 NAND Schmitt available that can be used in LTSpice? One that includes power supply connections and shows realistic supply currents, etc.

Or any of that fashion of CMOS family such as hex inverters that can also be used as negative-feedback analog amplifiers

Reply to
bitrex
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There is such a model in VSM (Labcenter / Proteus). Robert

Reply to
Robert Lacoste

If you have Helmut's 74HC devices installed, the 74HC132 is a dual NAND Schmitt device. I don't know about the supply current - CMOS devices are extremely low current drain in DC static condition. The current drain increases when driving a capacitive load as the frequency increases, but I don't know if that shows up in Helmut's 74HC devices.

The 74HC14 is a Schmitt inverter. You may run into problems using a Schmitt device in negative-feedback analog amplifiers.

A possible solution is a non-Schmitt device such as a 74HC04, but this may have too much gain since it is a triple stage device.

The 74HCU04 may be better suited for analog work since it is a single stage device. In either case, the drain current increases dramatically when the device is used near the switching threshold since both sides of the totem pole output are on.

Reply to
Steve Wilson

Thanks, I was interested in playing around with the "micropower boost" circuit using a 4093 someone posted a while back:

which "abuses" the power supply connection to generate the boost voltage; the CD4000_v.lib that's available for LTSpice seems to reflect variations in the supply unidirectionally; that is you can ride a sine wave on top of a Schmitt oscillator's VDD supply and see that in the output, but anything occurring with independent sources on the output node doesn't seem to be reflected to VDD.

Reply to
bitrex

The CD.../74HC... models provided in both LTspice _and_ PSpice are _behavior_ and not suitable for any analog simulation.

You _could_ roll you own CD4093 Spice model using either...

CA3046_3086_3127_CD4007.zip

or

CD4007_SPICE_MODEL.pdf

on the Device Models & Subcircuits Page of my website. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

I have a complete CD4001 model based on the RIT transistor models (some tweaking was necessary; this model is verified against the real IC):

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You'd have to add the schmitt trigger input circuit (also change the core logic function to NOR).

If your circuit does not rely on the schmitt trigger action, or creates its own (like the traditional 3-gate RC oscillator does), this will work as-is.

Tim

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Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
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Reply to
Tim Williams

Thanks, should be a good starting point if it turns out I'd like to roll my own

Reply to
bitrex

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