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Topic: Electrical impedance of Dout port (Read 3 times) previous topic - next topic


You're absolutely correct about my logic, I didn't think past my usually-DC uses.  I am rather surprised by your results, however, as the specs on these would imply otherwise.  From the TI data sheet for the archetype CD4066B:
Low Crosstalk Between Switches: ?50 dB
Typical at fis = 8 MHz, RL = 1 k?

Frequency Response, Switch On = 40 MHz



While that is what the spec sheet says, this is only true when layer out on a PCB with ground plane and terminated correctly. In other words it is the best you will get not what you will get.


Dec 01, 2012, 04:43 pm Last Edit: Dec 01, 2012, 04:46 pm by dr.benway Reason: 1
I did the following modification in the schematic, so no more overshoots now.  ]:D

The resistor is 47 ohm, the capacitor is 10 nF

The current input of the switch is almost zero.

I'm working with analog devices  adg419


The problem is the frequency.

Now with arduino duemilanove I'm working @ 10 khz but in future I will arrive at 1 mhz or more, so don't know if this is the right switch design for HF.

The biggest trouble now is the op-amp : it works perfectly for 10 minuts and after go on strike!
I have already burned two.  =( =( =(

So, where is the problem now?

Anyway, I solved the  problem of topic : I NEED THIS RC NETWORK.

100000 thanks 8)


Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.


Have you tried it with 1mhz yet? You can get a 50%duty cycle 1mhz square wave from the 328 pretty easy, tho idont remember offhand its only a few lines of code
I would suggest making a (few) prototype pcb from batchpcb or similiar , making it as tight together as possible, will ground plane, and then check again for your overshoot, you may find its entirely related to the prototyping method you are using

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