How to control DC voltage and current?
RF Transistor measurements can be particularly challenging when dealing with DC power supply control. IVCAD allows the DC power supply remote control of up to 6 accesses with associated DC or pulsed voltage and current measurements from the power supplies or using DC precision multimeters and oscilloscopes for pulsed current measurements when the RF signal is pulsed by an RF pulse modulator.
It is very easy to enter various and numerous DC power supply settings for the software GUI without any specific programming skills.
The generation and measurement are set separately for more flexibility. Power ON and OFF sequencing is customizable for DUT protection as well as the timing between each instrument.
How to Calculate a Voltage Drop Across Resistors?
It is a must-have to measure accurate DC voltages at the Device Under Test reference plane (DUT), whatever the current consumption. Because the current can flow through a cable with a parasitic serial resistance or through a shunt resistor for differential current measurements, the voltage drop across the serial or possibly parallel resistors must be taken into account to measure the true voltage at the DUT bias access. A resistive network can be configured into the IVCAD DC power supply user interface to de-embed the measurements and the voltage settings to the DUT reference plane.
How to Measure DC or Pulsed Current?
DC current can be measured simply by reading back the DC current from the DC Power supply through remote control. Nevertheless, it is preferable to use precision DC multimeters plugged in series on the DC path when high current measurement accuracy is needed. IVCAD enables a seamless DC setup configuration when DC power supplies and DC voltage and current multimeters are used. An oscilloscope can also be used to measure both DC / Pulsed Voltage and Current. Contact us to check the oscilloscope’s drivers, which are available.
When dealing with complex setups to characterize Transistors in pulsed conditions, it is easy to face the issue of instrument synchronization, especially when using different instruments from different vendors and different generations. For example, some RF sources can generate a fixed output synchronization signal with 50nsec width, but most of the triggered instruments like Power Meters; DMMs… have a minimum trigger hold-off timing of 1usec, resulting in a bad synchronization and wrong measurements, as well as software timeouts.
In this case, it is recommended to advantageously use a Trigger Box with the RF Modulator to help build a robust bench for transistors’ Pulsed Characterization.