Sine wave to Square wave (TTL/CMOS) converter?

[pavjayt]

I would like to build a circuit that I can use to convert a sine wave (0.4V to 10Vpp DC) to a square wave without any or very min delay and I would like the output to be of the same frequency as the input. I have been looking at comparators with reference votlages, but they all have huge delays for my taste. The sine wave will be a fixed frequency between(14KHz - 16Khz) and is very stable. The square wave output can be a TTL/CMOS level. It will be connected to a 4046PLL or HC14 schmitt trigger.

Any suggestions?

thanks

 

[JimB]

Maybe use an op-amp with very high gain so that it clips the tops of the sine waves, then use a schmitt to square up the rise and fall times of the clipped sine wave.

JimB

 

[crutschow]

What do you call a "huge delay"? Delay with respect to what?

 

[pavjayt]

Maybe use an op-amp with very high gain so that it clips the tops of the sine waves, then use a schmitt to square up the rise and fall times of the clipped sine wave.

JimB

Thanks Jim, actually I thought of this way, then read a lot online that this is not a good way to do it. But, I guess I can give it a try. Then the max input voltage for Schmitt trigger is 7V while mine goes to atleast 8V at its max.

 

[pavjayt]

What do you call a "huge delay"? Delay with respect to what?

When I said delay, its compared to input signal (sine wave). Some of the comparators I saw on digikey have ~15us delay to the output.

 

[crutschow]

How about an LM339, a common comparator, which has a delay of about a microsecond.

 

[jjw]

When I said delay, its compared to input signal (sine wave). Some of the comparators I saw on digikey have ~15us delay to the output.

There are comparators with a delay < 45ns.
Google ultra fast comparator.

 

[alec_t]

Perhaps just apply the sine wave via a cap to a CMOS gate (e.g. CD4049 or CD4050) resistor-biased to half the supply voltage (assumed 12V if your sine is 10Vpp)? Delay ~30ns.