ABSTRACT
Pulsed measurements ascertain the radio-frequency (RF) behavior of transistors or other devices at an unchanging bias condition. A pulsed measurement of a transistor begins with the application of a bias to its terminals. When the behavior of the device is bias- or rate-dependent, pulsed measurements yield the correct high-frequency behavior because the bias point remains constant during the measurement. Pulsed measurements are used to acquire characteristic curves that are free of dispersion effects. Pulsed measurements can extend to regions outside the safe-operating area without stressing or damaging the device. If the pulses are sufficiently short, there is no permanent change in the characteristic curves. Pulsed measurements yield an extended range of characteristic curves for a device that, at specific operating conditions, corresponds to the high-frequency behavior of the device. Devices operating in small-signal conditions give a nearly linear response, which can be determined by steady-state RF measurements made at the quiescent point.
