Some advice for the final step of the haardware design of Scanalogic 2

[ikalogic]

Some advice for the final step of the hardware design of Scanalogic 2

Hello,

some of you here know that i am working on scanalogic 2 (the second version of this logic analyzer **broken link removed**)

The problem is that i want to add some protection between the probes and the inputs of the logic circuits and the Micro controller.

I want to add something like 100K resistors at the input, but i am afraid it would affect the propagation delay as i am working on 25 MSPS.

I cannot post the schematic now, but the probes feed directly a 74374 D-Latch and an ATMEGA88 µC. and i want to add resistors inbetween the probes and the rest of the circuit.

Is is a good idea? what value should i use? is there another better practice?

(i don't think i can afford a buffer IC in terms of footprint space on the PCB...)

Thanks a lot for your advices...

 

[ikalogic]

was my question too stupid or too complex? lol

 

[be80be]

No you just posted in the wrong place you know how a bunch of EE are picky.
Now they have this LOL AVR - Electronic Circuits Projects Diagrams Free
But I would think you would get more help here https://www.electro-tech-online.com/forums/electronic-projects-design-ideas-reviews/

 

[3v0]

It is not too stupid.

How much does it cost to replace the AVR if you blow it?

Maybe the right option is to leave it exactly as it is.

3v0