Puzzle 25 of 100

Three inputs

Goal

Make Y low only while A, B, and C are all high.

Die: 13 by 15 squares
Layers: Metal, Polysilicon, Contact, N active, P active, N well
Inputs: A, B, C
Output: Y
Supply: VDD
Ground: GND

Hint

Extend the NAND gate: three P transistors side by side and three N transistors in series. Each input's polysilicon line forms one P transistor and one N transistor.

Solution

This is the game's reference drawing for the puzzle. It meets the goal and passes the design rules. Other drawings can pass as well.

Top View of the solved die for puzzle 25, Three inputs, with the Side View below it. — Top View of the solved die, captured from the game. Paths that carry a high level at the moment shown are lit. The Side View below cuts through the row between the dashed lines.

The game window in Isometric View with the solved die for puzzle 25, Three inputs, the guide, and the scope. — The whole game window in Isometric View. The scope on the right compares each output with its target band, and the message above it confirms that the drawing passes.

Solution drawing for puzzle 25, Three inputs, drawn on a numbered grid with every layer in its game color and pattern. — The solution on the grid. Squares are numbered from the top left corner, so you can count them. The dashed outline marks the squares you draw, change, or erase; the rest is drawn when the puzzle opens.

Legend

Metal58 squares
Polysilicon39 squares
Contact13 squares
N active7 squares
P active14 squares
N well44 squares
Input padA, B, C
Output padY
Supply padVDD
Ground padGND
Squares you draw, change, or erase88 squares

About the drawing

The drawing uses 111 of the die's 195 squares.
Part of the drawing is in place when the puzzle opens. To finish it, paint 85 empty squares and change 3 drawn squares.
It forms 6 transistors: 3 N transistors and 3 P transistors. Each one is a place where polysilicon crosses active silicon.
13 contacts join metal to the polysilicon or active silicon under it.

Starting drawing for puzzle 25, Three inputs, on a numbered grid. — The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.