Puzzle 33 of 100

Two pairs

Goal

Make Y low while A and B are both high, or while C and D are both high.

Die: 14 by 15 squares
Layers: Metal, Polysilicon, Contact, N active, P active, N well
Inputs: A, B, C, D
Output: Y
Supply: VDD
Ground: GND

New in this puzzle

Around other lines

Metal cannot cross other metal on the same layer. When the contacts of one node lie on both sides of other lines, join some of them below the strip and the rest above it.

Hint

In the N strip, the two series pairs run from GND to Y and back to GND. In the P strip, the node between the two pairs has three contacts: join two of them under the strip and two above it, so that the lines to VDD and to Y can pass. Start the P strip one row lower to leave room above it.

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 33, Two pairs, 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 33, Two pairs, 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 33, Two pairs, 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

Metal70 squares
Polysilicon52 squares
Contact13 squares
N active9 squares
P active18 squares
N well22 squares
Input padA, B, C, D
Output padY
Supply padVDD
Ground padGND
Squares you draw, change, or erase56 squares

About the drawing

The drawing uses 118 of the die's 210 squares.
Part of the drawing is in place when the puzzle opens. To finish it, paint 38 empty squares and change 18 drawn squares.
It forms 8 transistors: 4 N transistors and 4 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 33, Two pairs, on a numbered grid. — The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.