Hot TDR Measurements of Active Devices Using ENA Option TDR
Application Notes
Introduction
Impedance matching is essential in the design of high speed applications, because signal reflections due to impedance mismatches may have a significant impact on signal integrity. Since transmitters and receivers may cause significant reflections, they should be evaluated with great care. In fact, many modern high speed digital standards specify limits for impedance and return loss. Most of the standards require that the devices be operating during measurements, because the device characteristics are different between the power-on state and the power-off state. The purpose of this application note is to describe an effective evaluation method for the impedance measurement of active devices under actual operating conditions.