PVX-2505

The PVX-2505 pulse generator is designed for pulsed I-V (current-voltage) characterization of semiconductor devices at up to 50 Volts and 10 Amps. It is also well suited for other applications requiring high current, precision voltage pulses.

The I-V characteristics of semiconductor devices are functions of frequency and temperature. Curve tracers and other "DC" test systems typically step through a range of gate voltages and, at each gate voltage, sweep the drain voltage over the measurement range. The device essentially reaches thermal equilibrium and electronic (semiconductor-trap) equilibrium at each point, yielding different test characteristics than actual RF operational characteristics.

By pulsing the device using the PVX-2505 and taking a measurement during the pulse, the measurements can be taken before the device heats up. This circumvents the thermal effects associated with conventional "DC" testing, more closely approximates the characteristics of the device when operating at high frequencies, and doesn't activate the semiconductor "traps".

The PVX-2505 is designed using a bi-directional MOSFET output stage using DEI's DE-Series Fast Power MOSFETs. This design provides fast rise and fall times, with minimal overshoot, undershoot and ringing and fast settling times. This controlled voltage waveform allows the device under test (DUT) to stabilize at voltage within a few hundred nanoseconds, allowing I-V measurements to be made before device heating begins.

A quiescent (bias) voltage may be applied to the pulse generator, allowing the DUT to be held at a voltage other than zero, then pulsed above or below this voltage. The PVX-2505 requires an input gate signal, pulse (VHIGH) and optional quiescent (VLOW) DC power supply
inputs. The output pulse width and frequency are controlled by the input gate signal. The output voltage amplitude is controlled by the amplitude of the input VHIGH and optional VLOW DC power supply amplitudes.

The front panel controls and monitors provide the flexibility to operate in pulsed mode, or to switch to DC mode, in which the DC voltage generated by the VHIGH power supply is applied directly to the DUT. Integral instrumentquality voltage and current probes are provided to facilitate pulse data acquisition.

The output pulse is launched on an innovative, lowimpedance cable. The design of this cable maintains the fidelity of the output pulse without introducing pulse distortion or ringing, and provides a convenient means of connecting the pulse generator to the DUT or bias tee. The pulse generator is a direct-coupled, air-cooled solidstate design, offering equally fast pulse rise and fall times, low power dissipation, and minimal over-shoot, under-shoot or ringing. It has over-current detection and shut-down circuitry to protect the pulse generator from potential damage due to arcs and shorts in the load or interconnect cable.