Power n-MOSFET design for a 40-V 192-element thermal ink jet IC

A silicon-based thermal ink jet (TIJ) printhead which produces high-speed, laser-quality printing with a 300 spot per inch resolution has been designed, fabricated, and tested. The 5-V addressing logic, 13-V predriver circuitry, 40-V power MOSFET switches, and 192-drop ejectors are integrated on a single chip, and controlled by only seven external connections. The authors discuss the specific TIJ process and device design tradeoffs, especially focusing on the 40-V smart-power MOSFETs, and illustrate them with 2-D numerical modeling and experimental device data.