Circuits: VLSI

Puzzle 68 of 100

A block of two gates

Goal

Make Y the NAND of A and B, and Z their NOR. Both gates are drawn: wire each input to both gates, and each output to its pad.

Die
17 by 13 squares
Layers
Metal, Polysilicon, Contact, N active, P active, N well, Metal 2, Via
Inputs
A, B
Outputs
Y, Z
Supply
VDD
Ground
GND

Go to the solution

New in this puzzle

A block of cells

A block is a group of gates wired as one unit. Metal stays inside each gate, and metal 2 carries the wiring between the gates, over the cells.

Hint

Nothing passes the row on metal or polysilicon, so each input reaches the far gate on metal 2, and Y crosses the NOR gate on metal 2. Give each metal 2 line its own row so that no two of them touch.

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 68, A block of two gates, 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 68, A block of two gates, 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 68, A block of two gates, 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

  • Metal90 squares
  • Polysilicon47 squares
  • Contact19 squares
  • N active10 squares
  • P active20 squares
  • N well64 squares
  • Metal 240 squares
  • Via6 squares
  • Input padA, B
  • Output padY, Z
  • Supply padVDD
  • Ground padGND
  • Squares you draw, change, or erase43 squares

About the drawing

  • The drawing uses 171 of the die's 221 squares.
  • Part of the drawing is in place when the puzzle opens. To finish it, paint 18 empty squares and change 25 drawn squares.
  • It forms 8 transistors: 4 N transistors and 4 P transistors. Each one is a place where polysilicon crosses active silicon.
  • 19 contacts join metal to the polysilicon or active silicon under it.
  • 6 vias join metal 2 to the metal under it.
Starting drawing for puzzle 68, A block of two gates, on a numbered grid.
The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.