1 GHz divide-by-4

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This saves a relatively expensive EclipsLite flipflop. The delay line
could be a squiggly pcb trace... it's not super critical.


Version 4
SHEET 1 880 680
WIRE 64 -32 -80 -32
WIRE 256 -32 160 -32
WIRE 416 -32 336 -32
WIRE 64 0 32 0
WIRE 192 0 160 0
WIRE 32 32 32 0
WIRE 192 32 192 0
WIRE -80 160 -80 -32
WIRE 32 160 -80 160
WIRE 176 160 32 160
WIRE 32 208 -80 208
WIRE 176 208 32 208
WIRE 416 208 416 -32
WIRE 416 208 352 208
WIRE 464 208 416 208
WIRE 480 208 464 208
WIRE -80 240 -80 208
WIRE -80 368 -80 320
FLAG -80 368 0
FLAG 32 32 0
FLAG 192 32 0
FLAG 464 208 OUT
FLAG 32 208 CLK
FLAG 32 160 D
SYMBOL Digital\dflop 256 112 R0
WINDOW 0 -13 -35 Left 2
SYMATTR InstName A1
SYMATTR SpiceLine Td30%0p
SYMBOL voltage -80 224 R0
WINDOW 0 52 70 Left 2
WINDOW 3 24 119 Left 2
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value PULSE(0 1 0 100p 100p 400p 1n)
SYMBOL tline 112 -16 R0
WINDOW 0 2 -80 Bottom 2
WINDOW 3 4 -66 Top 2
SYMATTR InstName T1
SYMATTR Value Td=1.2n Z050%
SYMBOL res 352 -48 R90
WINDOW 0 -40 56 VBottom 2
WINDOW 3 -35 56 VTop 2
SYMATTR InstName R1
SYMATTR Value 50
TEXT 478 337 Left 2 !.tran 20n
TEXT 472 24 Left 2 ;1 GHz Divide by 4
TEXT 456 64 Left 2 ;J Larkin  Dec 17, 2014

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John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: 1 GHz divide-by-4
On Wed, 17 Dec 2014 21:20:35 -0800, John Larkin


Check out the cool waveforms on the two ends of T1.


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John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: 1 GHz divide-by-4

John Larkin:
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I use a UBP1505 (from ebay of course) 3$

What are all those funny numbers you posted??





Re: 1 GHz divide-by-4

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The schematic as LTSpice I assume.





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Re: 1 GHz divide-by-4
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RF stuff! It won't divide by 4, and has no reset input, and has no
prop delay spec. I's probably a ripple counter with tons of delay and
a bad tempco on that delay.

And NEC keeps discontinuing things.


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John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: 1 GHz divide-by-4
John Larkin:

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Na, for div by 64 you get 6 flops for 3$
or you can tune to the 21th harmonic with a simple LC and a 30 cent transistor.


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This one's been around a while, use it as prescaler in frequency counter.
It is not inherently stable though, it will self-oscillate without input.
So it is usable as synchronizer too :-)


Re: 1 GHz divide-by-4
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Let it oscillate and count the output frequency. That would make a
nice temperature transducer.


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John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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Re: 1 GHz divide-by-4
John Larkin:

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http://panteltje.com/panteltje/pic/temp_pic/

Re: 1 GHz divide-by-4
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Yup, CMOS has a terrible delay tempco. There's probably a diffused
resistor or something involved in there, too.

Lots of uPs and FPGAs how have some sort of on-purpose, on-chip temp
sensor.

I was just studying someone's timing product. It must have 20 CMOS
tiny-logic chip delays from input to output, figure 10ish ps/K delay
tempco each. I sure hope they temperature compensate some of that!


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John Larkin         Highland Technology, Inc
picosecond timing   laser drivers and controllers

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