Circuits: VLSI

Puzzle 6 of 100

Resistance in squares

Goal

Make Y read one third of the 5 V supply, about 1.7 V.

Die
12 by 14 squares
Layers
Metal, Polysilicon, Contact
Output
Y
Supply
VDD
Ground
GND

Go to the solution

New in this puzzle

Resistance in squares

Each square along a polysilicon strip adds the same resistance. A contact partway along a strip reads a voltage between the voltages at its two ends.

Hint

Polysilicon resists current, and each square of a strip adds the same resistance. Run polysilicon from VDD to GND and place a contact to Y with twice as many squares above it as below 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 6, Resistance in squares, 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 6, Resistance in squares, 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 6, Resistance in squares, 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

  • Metal14 squares
  • Polysilicon12 squares
  • Contact3 squares
  • Output padY
  • Supply padVDD
  • Ground padGND

About the drawing

  • The drawing uses 23 of the die's 168 squares.
  • The die starts empty, so you draw every square.
  • 3 contacts join metal to the polysilicon or active silicon under it.