[SI-LIST] subscribe: drive ability

 dear sir,
      I'm confused with the drive= ability calculation . When designed 
  the circuit, we have to con= sider the drive strength of the drive 
pin. It is said that the maximum = output current of drive pin should 
be more than the sum of all input pi= n driven.   But i don't know 
which current i should use to ca= lculate. Maybe we can divide all the 
time into two phase: the transient= phase and the stable phase. In the 
transient phase, the switches are t= o be closed and all of the 
parasitical capacitors , include output pin = parasitical capacitor, 
transmission line ,input pin parasitical capacit= or and so on, are 
charged. During this time, the value of current is la= rge, but the 
persistence time is short.  In the stable phase, the = current in the 
circuit is only the leakage current of CMOS gate and its= value is 
small ,but it lasts a long time.

   &nb= sp; When i calculate the drive  ability, which current should be 
u= sed,the transient current or the stable current.

   &= nbsp;           &nbs= p;    Best wishes .


--=20 

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