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???
12/24/09 21:25
Modified:
  12/24/09 23:55

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Msg Score: +2
 +2 Good Answer/Helpful
#171913 - DC and AC tests
Responding to: ???'s previous message
Admitance (usually Y) is a complex expresion of conductance (usually G) and suceptance (usually B). It means that Y= G + jB, where both G and B are frequency deppendant.

For Common Source:
Transconductance (or mutual conductance) is defined as dId/dVgs. You can easily get it from the Id versus Vgs plots: it is the value of the tangent of the slope of the plot in each point. Of course, this is a DC value.

Your data sheet gives a value for 100MHz. Measuring exactly this value is not easy. But you can get some reference value assuming that Vo= Vi* Rl* |Ygs|, where Vo is output voltage in drain, Vi is input voltage in gate (drain to ground for RF), Rl is some load resistor in drain (50 Ohm for example) and |Ygs| is the transconductance modulus. So |Ygs|=Vo/(Vi*Rl)

You would need a RF generator, the setup with the J309, and an oscilloscope with adequate BW and low capacity test probe.

Similar idea can be used for common gate.

Rest of parameters are more difficult to measure without very special instruments and good knowledge.

Good luck and Merry Christmas!

Daniel

List of 23 messages in thread
TopicAuthorDate
Device characterization            01/01/70 00:00      
   DC tests and DC tests            01/01/70 00:00      
      DC test            01/01/70 00:00      
      As I said you need AC and DC tests            01/01/70 00:00      
         Not necessarily...            01/01/70 00:00      
   Datasheet?            01/01/70 00:00      
      None unfortunately            01/01/70 00:00      
         What about other datasheets            01/01/70 00:00      
   Datasheet?            01/01/70 00:00      
      datasheet            01/01/70 00:00      
         I would give this a try...            01/01/70 00:00      
   DC and AC tests            01/01/70 00:00      
      Very useful (but still some confusion)            01/01/70 00:00      
         Some answers...            01/01/70 00:00      
            Rds versus Vgsoff...            01/01/70 00:00      
               Exact match            01/01/70 00:00      
                  But with higher Rdon            01/01/70 00:00      
                     Should not be important            01/01/70 00:00      
                     Which one?            01/01/70 00:00      
                        "the amplifier circuit"            01/01/70 00:00      
                           Ri versus Rds(on)...            01/01/70 00:00      
                              Higher Rd(on) affects Ri?            01/01/70 00:00      
                                 Rd(on) versus gain            01/01/70 00:00      

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