Reply by Anthony William Sloman●September 18, 20222022-09-18
On Sunday, September 18, 2022 at 9:46:00 AM UTC+10, John Larkin wrote:
> On Sat, 17 Sep 2022 15:52:34 -0700 (PDT), Lasse Langwadt Christensen
> <lang...@fonz.dk> wrote:
>
> >lørdag den 17. september 2022 kl. 23.45.50 UTC+2 skrev John Larkin:
> >> LT Spice, Dflop:
> >>
> >> I can set VHIGH = 5 and that works.
> >>
> >> But if I add TRISE = 500p then VHIGH reverts to 1 volt.
> >>
> >
> >works just fine,
> >
> >Version 4
> >SHEET 1 880 680
> >WIRE 304 48 64 48
> >WIRE 64 160 64 48
> >WIRE 96 160 64 160
> >WIRE 96 208 -112 208
> >WIRE 304 208 304 48
> >WIRE 304 208 272 208
> >WIRE -112 240 -112 208
> >WIRE -112 400 -112 320
> >FLAG -112 400 0
> >SYMBOL Digital\\dflop 176 112 R0
> >WINDOW 3 156 69 Left 2
> >SYMATTR InstName A1
> >SYMATTR Value VHIGH=5,TRISE=10m
> I tried commas, no help.
>
> DFLOP is weird. I had rout=1m, and that messed it up. With rout=0.1,
> it's OK.
>
> The flop output with trise=700p has a soft corner. A pulsed voltage
> source with the same specified rise time is sharp.
No surprise there. The bistable model is supposed to simulated a real part, and the pulsed voltage source is a mathematical abstraction.
--
Bill Sloman, Sydney
Reply by John Larkin●September 17, 20222022-09-17
On Sat, 17 Sep 2022 15:52:34 -0700 (PDT), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:
>l�rdag den 17. september 2022 kl. 23.45.50 UTC+2 skrev John Larkin:
>> LT Spice, Dflop:
>>
>> I can set VHIGH = 5 and that works.
>>
>> But if I add TRISE = 500p then VHIGH reverts to 1 volt.
>>
>
>works just fine,
>
>Version 4
>SHEET 1 880 680
>WIRE 304 48 64 48
>WIRE 64 160 64 48
>WIRE 96 160 64 160
>WIRE 96 208 -112 208
>WIRE 304 208 304 48
>WIRE 304 208 272 208
>WIRE -112 240 -112 208
>WIRE -112 400 -112 320
>FLAG -112 400 0
>SYMBOL Digital\\dflop 176 112 R0
>WINDOW 3 156 69 Left 2
>SYMATTR InstName A1
>SYMATTR Value VHIGH=5,TRISE=10m
I tried commas, no help.
DFLOP is weird. I had rout=1m, and that messed it up. With rout=0.1,
it's OK.
The flop output with trise=700p has a soft corner. A pulsed voltage
source with the same specified rise time is sharp.
Reply by Lasse Langwadt Christensen●September 17, 20222022-09-17
lørdag den 17. september 2022 kl. 23.45.50 UTC+2 skrev John Larkin:
> LT Spice, Dflop:
>
> I can set VHIGH = 5 and that works.
>
> But if I add TRISE = 500p then VHIGH reverts to 1 volt.
>
works just fine,
Version 4
SHEET 1 880 680
WIRE 304 48 64 48
WIRE 64 160 64 48
WIRE 96 160 64 160
WIRE 96 208 -112 208
WIRE 304 208 304 48
WIRE 304 208 272 208
WIRE -112 240 -112 208
WIRE -112 400 -112 320
FLAG -112 400 0
SYMBOL Digital\\dflop 176 112 R0
WINDOW 3 156 69 Left 2
SYMATTR InstName A1
SYMATTR Value VHIGH=5,TRISE=10m
SYMBOL voltage -112 224 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value SINE(2.5 2.5 10 0)
TEXT -146 424 Left 2 !.tran 1
Reply by John Larkin●September 17, 20222022-09-17
LT Spice, Dflop:
I can set VHIGH = 5 and that works.
But if I add TRISE = 500p then VHIGH reverts to 1 volt.
And incidentally, what's the difference between Spice Line 1 and
Spice Line 2? TRISE on either breaks VHIGH.
Building a pseurandom bit stream generator is too much work, but it's
easy to clock random junk into a flop.