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A simple question

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Hi There,

A need a component which gives the inkomming signal a 5ns delay if thats possible. I think I know that an inverter gives a 10ns delay. I just need to know the delay very accurate.
 
A short length of pcb wiring or just a short wire will give only a 5ns delay.
There are many logic families and each one has a different amount of delay.
 
audioguru said:
A short length of pcb wiring or just a short wire will give only a 5ns delay.

One would need about 30" of trace to get 5ns delay on FR4 circuit board.
 
Remember when 'scopes used some coax cable as a delay line? TVs use a small little delay line. Surface mount delay lines are available now.
 
eblc1388 said:
One would need about 30" of trace to get 5ns delay on FR4 circuit board.
And it would need to be terminated on at least one end in its characteristic impedance.
If he wants a digital delay, RC works if you aren't too fussy about accuracy, and the signal pulse width is more than about 15 - 20 ns.
 
audioguru said:
Remember when 'scopes used some coax cable as a delay line? TVs use a small little delay line. Surface mount delay lines are available now.

Very old colour TV's used to use a coil of coaxial cable for the luma delay line, later on they used a coil of wire around a former - these days it's done electronically inside a chip.

PAL sets also have a 64uS delay line, these were originally made out of glass, but are now internal to the chips.
 
So I just can't use a component, but a fixed lenght of the trace (the PCB) between the components could give a 5ns delay? Is it possible to get a very accurate delay maybe 10, 20 or 50ns by a component?
 
These have 5ns delays.

**broken link removed**
 
Nigel Goodwin said:
Perhaps you might care to explain what you're trying to with it?.

A quick calculation shows that electricity will travel about 1.5metres in 5nS.
Yes, but only in free space. In a transmission line, it is inversely proportional to the square root of the effective dielectric constant of the tline's dielectric.
FR4 epoxy-glass board has a dielectric constant of ~4.0 - 4.5, so the propagation velocity of stripline (sandwiched between two ground planes) is about half that of free space. Microstrip (surface line over gnd plane) effective dielectric constant is a function of geometry, but will always be less than the substrate's value, due to the fact that one side is exposed to air, which has a dielectric constant of 1. Values around 3.0 - 3.5 are typical.
 
Electronics4you said:
So I just can't use a component, but a fixed lenght of the trace (the PCB) between the components could give a 5ns delay? Is it possible to get a very accurate delay maybe 10, 20 or 50ns by a component?

You need to quantify HOW accurate. Something along the lines of 5ns +/- 100ps etc.. If you use logic parts that aren't specified for accurate delays, you will find that typically, they will be much faster than thei maximum datasheet value shows - doesnt sound like a good way to make an _accurate_ delay.
 
I'm building a simple - but accurate, LIDAR. I need a short delay between the FF's, so I with accuracy can determine, where the received signal is received in the signal. But I think I have to allow for trace lenght to get this accuracy. Like the MAX9010 comparator.
 
Electronics4you said:
I'm building a simple - but accurate, LIDAR. I need a short delay between the FF's, so I with accuracy can determine, where the received signal is received in the signal. But I think I have to allow for trace lenght to get this accuracy. Like the MAX9010 comparator.
MAX9010 does not guarantee 5ns delay. Look at the datasheet. It can be as much as 10ns, and I'm guessing might be as low as 3 or 4 ns.
 
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