Puzzle 39 of 100

A strong compound gate

Goal

Y now drives a large load. Widen the transistors so that both edges are at least as fast as the target.

Die: 13 by 19 squares
Layers: Metal, Polysilicon, Contact, N active, P active, N well
Inputs: A, B, C
Output: Y
Supply: VDD
Ground: GND

New in this puzzle

The slowest path

A compound gate is only as fast as its slowest path to each rail. Size each strip for the path with the most transistors in series.

Hint

Y falls through A and B in series, and rises through A or B in series with C. Each strip has two transistors in series on its slowest path, so each needs twice the width that one transistor would need for the same load.

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 39, A strong compound gate, 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 39, A strong compound gate, 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 39, A strong compound gate, 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

Metal76 squares
Polysilicon48 squares
Contact25 squares
N active14 squares
P active28 squares
N well66 squares
Input padA, B, C
Output padY
Supply padVDD
Ground padGND
Squares you draw, change, or erase21 squares

About the drawing

The drawing uses 145 of the die's 247 squares.
Part of the drawing is in place when the puzzle opens. To finish it, paint 1 empty square and change 20 drawn squares.
It forms 6 transistors: 3 N transistors and 3 P transistors. Each one is a place where polysilicon crosses active silicon.
25 contacts join metal to the polysilicon or active silicon under it.

Starting drawing for puzzle 39, A strong compound gate, on a numbered grid. — The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.