Forums

LT Spice diode c-v

Started by John Larkin February 18, 2017

A diode model looks like

.model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m
Vpk=75 mfg=OnSemi type=silicon)

If I want to model some other diode c-v curve, I can edit Cjo as
needed. But what parameter would change the shape of the curve, how c
declines with voltage?

I'm modeling a weird photodiode and I can get close to the actual
datasheet values, but the shape is a little off.


-- 

John Larkin         Highland Technology, Inc

lunatic fringe electronics 

Den søndag den 19. februar 2017 kl. 04.32.40 UTC+1 skrev John Larkin:
> A diode model looks like > > .model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m > Vpk=75 mfg=OnSemi type=silicon) > > If I want to model some other diode c-v curve, I can edit Cjo as > needed. But what parameter would change the shape of the curve, how c > declines with voltage? > > I'm modeling a weird photodiode and I can get close to the actual > datasheet values, but the shape is a little off. >
Fc? http://ltwiki.org/LTspiceHelp/LTspiceHelp/D_Diode.htm
On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s&#2013266168;ndag den 19. februar 2017 kl. 04.32.40 UTC+1 skrev John Larkin: >> A diode model looks like >> >> .model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m >> Vpk=75 mfg=OnSemi type=silicon) >> >> If I want to model some other diode c-v curve, I can edit Cjo as >> needed. But what parameter would change the shape of the curve, how c >> declines with voltage? >> >> I'm modeling a weird photodiode and I can get close to the actual >> datasheet values, but the shape is a little off. >> > >Fc? > >http://ltwiki.org/LTspiceHelp/LTspiceHelp/D_Diode.htm
Fc is a forward-bias parameter. I could try things, but I was hoping some guru would know. -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Sat, 18 Feb 2017 20:23:16 -0800, John Larkin
<jjlarkin@highlandtechnology.com> wrote:

>On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen ><langwadt@fonz.dk> wrote: > >>Den s&#2013266168;ndag den 19. februar 2017 kl. 04.32.40 UTC+1 skrev John Larkin: >>> A diode model looks like >>> >>> .model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m >>> Vpk=75 mfg=OnSemi type=silicon) >>> >>> If I want to model some other diode c-v curve, I can edit Cjo as >>> needed. But what parameter would change the shape of the curve, how c >>> declines with voltage? >>> >>> I'm modeling a weird photodiode and I can get close to the actual >>> datasheet values, but the shape is a little off. >>> >> >>Fc? >> >>http://ltwiki.org/LTspiceHelp/LTspiceHelp/D_Diode.htm > >Fc is a forward-bias parameter. I could try things, but I was hoping >some guru would know.
This looks like it, sheet 15: www.keysight.com/upload/cmc_upload/All/Diode.pdf -- John Larkin Highland Technology, Inc lunatic fringe electronics
On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s&#2013266168;ndag den 19. februar 2017 kl. 04.32.40 UTC+1 skrev John Larkin: >> A diode model looks like >> >> .model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m >> Vpk=75 mfg=OnSemi type=silicon) >> >> If I want to model some other diode c-v curve, I can edit Cjo as >> needed. But what parameter would change the shape of the curve, how c >> declines with voltage? >> >> I'm modeling a weird photodiode and I can get close to the actual >> datasheet values, but the shape is a little off. >> > >Fc? > >http://ltwiki.org/LTspiceHelp/LTspiceHelp/D_Diode.htm
Use the "idealized" model at your own peril. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions.
On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s&#2013266168;ndag den 19. februar 2017 kl. 04.32.40 UTC+1 skrev John Larkin: >> A diode model looks like >> >> .model 1N4148 D(Is=2.52n Rs=.568 N=1.752 Cjo=4p M=.4 tt=20n Iave=200m >> Vpk=75 mfg=OnSemi type=silicon) >> >> If I want to model some other diode c-v curve, I can edit Cjo as >> needed. But what parameter would change the shape of the curve, how c >> declines with voltage? >> >> I'm modeling a weird photodiode and I can get close to the actual >> datasheet values, but the shape is a little off. >> > >Fc? > >http://ltwiki.org/LTspiceHelp/LTspiceHelp/D_Diode.htm
M, FC, VJ... <http://www.analog-innovations.com/SED/DiodeCapacitance.png> ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Thinking outside the box... producing elegant solutions.