Puzzle 65 of 100

Supply straps

Goal

Make Y the inverse of A and Z the inverse of B. The VDD pad reaches only the upper VDD rail, and the GND pad only the lower GND rail.

Die: 13 by 25 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

Supply straps

A strap of metal 2 joins the rails of several rows to one pair of supply pads. It passes over the rails it does not join and reaches its own rails through vias.

Hint

Join the two VDD rails with a strap of metal 2 that passes over the GND rail between them, and join the two GND rails the same way. Each strap needs a via on both rails it joins, and the two straps must not 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 65, Supply straps, 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 65, Supply straps, 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 65, Supply straps, 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

Metal98 squares
Polysilicon22 squares
Contact14 squares
N active10 squares
P active20 squares
N well72 squares
Metal 228 squares
Via4 squares
Input padA, B
Output padY, Z
Supply padVDD
Ground padGND
Squares you draw, change, or erase28 squares

About the drawing

The drawing uses 190 of the die's 325 squares.
Part of the drawing is in place when the puzzle opens. To finish it, paint 16 empty squares and change 12 drawn squares.
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.
4 vias join metal 2 to the metal under it.

Starting drawing for puzzle 65, Supply straps, on a numbered grid. — The drawing when the puzzle opens. The dashed outline marks the squares the solution changes.