OK, 4x 22 Ohm parallel (5.5 Ohm) from driver output to ground.
First screenshot overall signal at 13.5MHz, looking good:
yellow: input from FG
Blue: output from driver to ground
Next 2 screenshots are zoomed in on the rise / fall times of 4.5MHz, then 13.5MHz (look at the increased delay on 13.5MHz)
Also looking good, the 4x 22 Ohm resistors getting hot fast.
Looks like the IXIS driver can rise in 7ns with almost 3A flowing through it (I assume 15V V CC). That is pretty quick. The phase shift is caused by the driver's propagation delay (30ns) but this delay is not the same as the rise time. To further characterize this driver's performance under heavy load you can use one 1/4W 1.5Ω carbon resistor to stress the driver even more, but to prevent this resistor from burning up you should use very sparse pulses (low duty cycle). If you had your versatile Rigol generator, you'd set it up like this: 1) Set CH1 of your signal generator to the Square waveform (Period: 100ns, StartPhase: 0º, Duty Cycle: 50%) 2) Set the Burst mode of CH1 to (Type: N_Cycle, Cycles: 1, Burst Period: 20ms., StartPhase: 359.999º, Source: Internal, Delay: 0 ). This will set your signal generator to output a 100ns positive pulse every 20 milliseconds (very low duty cycle) that will not burn up the resistor even if there is more than 10A flowing through it. If you want to test the fall time under load (sinking performance) jest connect the load resistor to V CC. Of course MOSFETs present capacitive loads to the driver, which is a little different because at the beginning of the pulse capacitors behave like a 0Ω resistor (short) and after 5 RC constants they behave almost like infinite resistance (open). This is further complicated by the Miller effect, but we won't go there for the driver performance characterization alone. One remedy for the Miller effect is cascode configuration.
« Last Edit: 2015-06-19, 17:41:57 by verpies »
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Topic: "RF and molecular bond breaking Kanzius style" (Read 121716 times)
