Circuits: VLSI

Puzzle 15 of 100

Balanced edges

Goal

Draw the P transistor so that Y rises as fast as it falls.

Die
14 by 14 squares
Layers
Metal, Polysilicon, Contact, N active, P active, N well
Input
A
Output
Y
Supply
VDD
Ground
GND

Go to the solution

New in this puzzle

Channel width

A wider channel passes more current, so its transistor switches a load faster. The width is the number of squares along each side of the gate.

Hint

A P channel conducts about half as well as an N channel of the same size. The N transistor here is two squares wide.

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 15, Balanced edges, 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 15, Balanced edges, 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 15, Balanced edges, 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

  • Metal57 squares
  • Polysilicon12 squares
  • Contact13 squares
  • N active10 squares
  • P active20 squares
  • N well48 squares
  • Input padA
  • Output padY
  • Supply padVDD
  • Ground padGND
  • Squares you draw, change, or erase48 squares

About the drawing

  • The drawing uses 104 of the die's 196 squares.
  • Part of the drawing is in place when the puzzle opens. To finish it, paint 40 empty squares and change 8 drawn squares.
  • It forms 2 transistors: 1 N transistor and 1 P transistor. 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 15, Balanced edges, on a numbered grid.
The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.