An analog-mixed-signal system-on-a-chip can be a combination of analog circuits, digital circuits, intrinsic mixed-signal circuits, and embedded software. Integrated circuits (ICs) are generally classified as digital (e.g. a microprocessor) or analog (e.g. an operational amplifier). Mixed-signal ICs are chips that contain both digital and analog circuits on the same chip. This category of chip has grown dramatically with the increased use of 3G cell phones and other portable technologies.