On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s�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.

Reply by Jim Thompson●February 19, 20172017-02-19

On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s�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.

Reply by John Larkin●February 19, 20172017-02-19

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�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

Reply by John Larkin●February 19, 20172017-02-19

On Sat, 18 Feb 2017 19:49:03 -0800 (PST), Lasse Langwadt Christensen
<langwadt@fonz.dk> wrote:

>Den s�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

Reply by Lasse Langwadt Christensen●February 18, 20172017-02-18

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.
>

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