NG-SPICE: Low-Powered Saw-Wave Generator, Revisited.

This posting attempts to resolve the inadequacies of the circuit that I had already designed, using the Open-Source package ‘NG-SPICE’, and that I had described in This Earlier Posting.

Essentially there was only one problem which I was able to resolve: The bad input and output impedances of the former circuit. I now have a circuit with an input impedance of approximately 100kΩ, and an output impedance of approximately 10kΩ. A source-follower resistor for the output can be substituted where R3 is, to halve the impedance further, at the cost of also attenuating the output amplitude slightly more…

Saw_2

Screenshot_20190630_020651

These were the SPICE Model-Cards used:

http://dirkmittler.homeip.net/text/NMOS1.mod.txt

http://dirkmittler.homeip.net/text/BAS16W.mod.txt

Please do not attempt to build this circuit using discrete components. As already described in the previous, main posting, the ultra-low capacitances used in this circuit will get overpowered by stray capacitance which breadboards, wires, etc. will introduce. This circuit can only be implemented as part of a larger circuit, on the same IC. Therefore, it should only be considered hypothetical.

(Updated 7/4/2019, 8h20 … )

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