1. General description The UCB1400 is a stereo audio codec equipped with touch screen and power management interfaces. It integrates an AC ’97 Rev. 2.1 interface for communication to an AC link host controller such as the Intel Xscale™ processor. The stereo audio codec inputs connect directly to a microphone or line level sources such as a CD player. The stereo audio codec outputs at line level and can drive a headphone directly. The touch screen interface connects directly to a 4-wire resistive touch screen. A built-in 10-bit analog-to-digital converter provides readout of touch screen and power management parameters. Ten general-purpose I/O pins provide programmable inputs and/or outputs to the system. 2. Features n 48-pin LQFP surface mount package and low external component count for minimal PCB space requirement n Integrated AC ’97 Rev. 2.1 interface n 20-bit stereo audio codec supporting programmable sample rates, and input/output gain control u Stereo line input and mono microphone input u Stereo line/headphone output with bass/treble control u Headphone driver with short circuit protection and virtual ground for DC coupling n 4-wire resistive touch screen interface circuit supporting position, pressure and plate resistance measurements n 10-bit successive approximation ADC with internal track-and-hold circuit and analog multiplexer for touch screen readout and monitoring of four external high voltage (7.5 V) sources n Ten general purpose input/output pins n 3.3 V supply voltage and built-in power saving modes for portable and battery powered applications. 3. Applications n Smart mobile phones n Handheld PCs n Palm-top PCs n Personal Intelligent Communicators (PIC) n Personal Digital Assistants (PDA).