Abstract: A method and circuit for adjusting packaged device output characteristics without dedicated pads or pins are disclosed. As opposed to multiple bit selection for the purpose of trimming, the method utilizes an iterative and dynamic means to trim the bits of a built-in trimming network such as an impedance network one bit at a time. Trim time will be short because each single loop trim cycle is very short. The method is robust and not overly complicated thus may be implemented very practically. The system is dynamic in nature because the operation of the device to be trimmed need not be changed from one mode to another.