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Im trying design this function : (NOT Y)=A+BCD in CMOS my design in pic below now i want to design this function in Pseudo NMOS but i dont know how to design it in Pseudo NMOS.anyone can help please??enter image description here

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  • \$\begingroup\$ It won't work without a pull-up resistor. \$\endgroup\$ – Andy aka May 29 '17 at 14:55
  • \$\begingroup\$ @Andyaka how i add a pull-up resistor? \$\endgroup\$ – Memo May 29 '17 at 15:00
  • \$\begingroup\$ A pull-up resistor is a resistor which will pull up (make high) the output when all transistors which could pull the output down (low) are off. Now think where this resistor must be placed. Hint: one side of the resistor must connect to VDD, the supply voltage (which is invisible in your schematic). \$\endgroup\$ – Bimpelrekkie May 29 '17 at 15:19
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The name ``pseudo-NMOS'' originates from the circumstance that in the older NMOS technologies a depletion mode NMOS transistor with its gate connected to source was used as a pull-up device. http://www.iue.tuwien.ac.at/phd/schrom/node101.html

Pseudo-NMOS isn't totem pole output, just add a small PMOS pull-up.

Note: Depletion mode refers to the channel being inverted at Vgs = 0, similar to a typical JFET, you use the gate to pull the device out of conduction.

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