Puzzle 17 of 100

Two inverters make a buffer

Goal

Make Y follow A through two inverters in a row.

Die: 20 by 12 squares
Layers: Metal, Polysilicon, Contact, N active, P active, N well
Input: A
Output: Y
Supply: VDD
Ground: GND

Go to the solution

Hint

Connect the output of the first inverter to the polysilicon gate line of the second. Both inverters can share the VDD and GND rails.

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 17, Two inverters make a buffer, 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 17, Two inverters make a buffer, 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 17, Two inverters make a buffer, 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.

Legend

Metal79 squares
Polysilicon23 squares
Contact14 squares
N active10 squares
P active20 squares
N well60 squares
Input padA
Output padY
Supply padVDD
Ground padGND

About the drawing

The drawing uses 144 of the die's 240 squares.
The die starts empty, so you draw every square.
It forms 4 transistors: 2 N transistors and 2 P transistors. Each one is a place where polysilicon crosses active silicon.
14 contacts join metal to the polysilicon or active silicon under it.