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Kai Klaas
11/06/11 06:04
Modified:
  11/06/11 06:05

Read: 386 times
Germany


 
#184563 - Redesign your circuit!
Responding to: Arif Deshmukh's previous message
Arif said:
When its inputs are floating then its output should be at high impedance state.

Floating and high impedance state can never be active levels in any kind of circuit, because floating means, that there's no path to shunt interference to ground. A floating place is extremely sensitive to noise, leakage currents and charge injections from switchings. It's so sensitive, that a good developer avoids floating at all and always adds pull-ups or pull-downs.

Another disadvantage is, that a floating potential at the input of a CMOS-inverter can dramatically increase its power consumption.

And, finally, there is a conceptual mistake: How to detect floating at all? By the help of a potential? Well, each toggling from low to high or vice versa means a brief "floating" then...

Kai Klaas

List of 14 messages in thread
TopicAuthorDate
Non Inverting Buffer      Arif Deshmukh      11/05/11 21:32      
   3 states?      Andy Neil      11/06/11 00:53      
   are You sure?      Stefan KAnev      11/06/11 03:18      
      Describe the goal - not the step      Andy Neil      11/06/11 06:46      
         bidirectional driver      Jan Waclawek      11/06/11 06:56      
   Redesign your circuit!      Kai Klaas      11/06/11 06:04      
   You've described..        Oliver Sedlacek      11/07/11 04:54      
      Goal      Arif Deshmukh      11/07/11 06:07      
         "its input is kept floating" do you mean      Erik Malund      11/07/11 06:39      
         let's get down to low-level details      Richard Erlacher      11/07/11 07:21      
         Common Anode 7-segment display      Stefan KAnev      11/07/11 08:34      
            No need to float the signals      Per Westermark      11/07/11 08:56      
         Do not let inputs float...        Michael Karas      11/07/11 09:52      
      Absolutely Right.      Michael Karas      11/07/11 10:10      

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