pohotodiode in multisim 9

[vioamethyst]

hai
i wanna know how to get photodiode that function as photo detector in multisim 9?
what i found was only photo_diode_rated (component-rated virtual-photo_diode_rated) the component symbol with double arrow going out, so obviusly it is emitter and not a light detector
i need to design a hardware that will using plastic fiber optic photodiode detector to convert the light from fiber optic back to electrical signal then bla bla bla
one of the photodiode will be in use is sfh350, bt the problem is i cant find any component to be photodiode that acts as photo detector in multisim

i heard there is software that is suitable for optic application..if nt mistaken the software name is optisim (correct me if i am wrong), is it true? is it help in my hardware design?even it can, problem is, the software is expensive =(

if u have futher suggestion, just feel free to do so
i will gladly to hear ur views
pls guide me
thank u in advance guys

 

[dick_freebird]

Use a reasonably close diode model and parallel a current
source to model the photocurrent. You would need to learn
the transfer characteristics (incident light energy to current)
but that is probably available from the mfr or simple enough
to take bench data if you are set up with the optical source.

 

[vioamethyst]

may i know the step by step to make the model?hope u cn futher guide me

so there is no component that direclt function as fiber optic detector in multisim 9?

i will attach here the datasheet of fiber optic detector that i will be using which are
SFH551 and SFH350

 

[dick_freebird]

The '551 is not a photodiode - it's got a Schmitt buffer after it.

Datasheet tells you optical threshold (in watts). You may want
to fake that by an electrical representation for SPICE type
analysis (say, represent 1uW by 10mV or something).
Datasheet also gives you an indication of the linear band of
the input comparator, in that it requires 0.1uW or less to
guarantee a logic "1" (so estimate about a 12uW linear band
on the comparator front end).

You might want to model this with a vcvs, gain such that 12uW in
(or 120mV by my example) produces 5V - call it A=40 or so
if you use that scheme. But the open collector output would not
be well represented that way.

That is one mighty slow receiver by today's standards,
looks suitable for 10MBPS or under.

The '350 is a phototransistor (probably photodarlington,
judging by the advertised gain of 500). They give you a mA/uW
which, if you used the voltage analogue, would say that a vccs
might do the job for you, in parallel with the datasheet
capacitance numbers and whatever output pullup you like.

I don't use Multsim9. But you might want to hit the mfrs' support
pages and fish for macromodels, there may be some.

 

[vioamethyst]

wow...its really long explaination, am im rili greatful that u rili help in explaination,i will try to digest what u write bcos i dun have much knowledged in thing thing..its the first time i deal with real hardware design..so im kinda lack here and there

about that multisim 9, my design, i chose to use ADC0831 , and PIC16F84A too
so problematic, cos in the multisim 9 of mine, doest have the model as such...

anyway..im rili appreciate ur guidance, i will try my best to understand what u explain to me

thx again