Monday, February 01, 2010

New Touch-Screen Controllers Offer Robust Sensing for Portable Displays

Touch-screen displays are replacing mechanical buttons in smart phones, MP3 players, navigation systems, laptop computers, and other devices. First generation devices suffered from low accuracy, false detection, and high power consumption. New devices--which offer improved accuracy, lower power consumption, and result filtering--can also sense temperature, supply voltage, and touch pressure.

Driving PIN Diodes: The Op-Amp Alternative

PIN diodes, which sandwich a lightly doped intrinsic region between heavily doped P and N regions, are used extensively in RF and microwave applications. PIN diode drivers--which provide a controlled forward bias current and reverse bias voltage--use discrete designs or specialized ICs. As an alternative, widely available op amps can be used. Op amps in this class feature wide bandwidth, high slew rate, and enough steady-state current to drive PIN diodes.