关键词：移动应用程序；形式因素；外部参考电阻器
摘 要：The strong market demand for mobile applications such as iPhone makes value on the formfactor of the mobile devices. The form factor means how much we can integrate many functionsin a given size of the mobile devices. The external component size is almost comparable to achip size so that elimination of external component is crucial to the success of mobile devices inaddition to the cost issues of the external components. External reference resistors are often usedas the standard for calibrating voltage sources, current sources, and other component values within a circuit. Often these calibrations occur at a factory, but may also occur on an electronicdevice as it is used. However, external reference resistors consume area and cost and it is desirable to eliminate them.