Some of the smallest PCBs I’ve designed, these Gas Sensor boards are just 35 mm by 22 mm (1.38 inches x 0.88 inches) in size.
The board below is a four layer board using metric 1608 (inch 0603) SMT passives.
Toxic Gas Sensor PCB
The board below is a six layer board using metric 1005 (inch 0402) SMT passives.
Dual Toxic Gas Sensor PCB
Despite the small area available for component placement the designs were completed without having to use buried or blind vias.
