Resistance calibration method without external precision elements

Abstract

A method of resistance calibration without external precision elements usage presented in paper. In the proposed method, used structures which operation based on technologically accurate elements and signals to have high accuracy resistance after calibration. Architecture produces a calibration code corresponding to 50Ohms PVT compensated termination impedance, which is needed to avoid reflections in transmission lines. Standard calibration methods using external ~1% accuracy precision discreet resistance (50 or 200Ohms). The presented calibration mechanism using internal elements and can provide ~ 4-7% accuracy of calibration. Method can be used in the special input/output circuits of several standards such as Peripheral Component Interconnect (PCI), Universal Serial Bus (USB), Double Data Rate (DDR) etc.