January 19, 2012 -- Today's users expect multitouch systems to perform with precision and still comply with demanding environmental standards. Designers face no small feat in meeting these requirements. With a rapidly changing internal environment in multitouch systems, the war for touchscreen dominance is effecting the emergence of new battlegrounds.

One current trend is the push toward thinner phones. Achieving this goal means direct lamination of capacitive-touch sensors to the display, moving the sensor inside the display, and overcoming many other challenges with antennas and ground loading. It is no longer acceptable to just throw a shield layer onto the sensor structure to block display noise. Such an approach adds too much cost and thickness.

Beyond displays, the prevalence of USB-charging connectors has made battery chargers into commodities, pulling every last cent from these devices. Capacitive-touchscreen ICs now sense picocoulombs of change in the presence of as much as 40-V p-p ac noise. All of these factors add up to requirements for touchscreen ICs that are far more complex than what was required just last year. New innovations are needed, and so begin the noise wars.

By John Carey. (Carey is Director of Marketing for TrueTouch Technology at Cypress Semiconductor Corp.)