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

LROBBINS

Grumpy,
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:
Quote
Low Crosstalk Between Switches: ?50 dB
Typical at fis = 8 MHz, RL = 1 k?

and
Quote
Frequency Response, Switch On = 40 MHz
Typical

Ciao,
Lenny

Grumpy_Mike

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.

dr.benway

#32
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

http://www.analog.com/static/imported-files/data_sheets/ADG419.pdf

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)

dc42

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.

winner10920

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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