Datasheet - To - Device Model??

Greetings,

In the last few days, I've had a lot of success in creating device
models for the CM6 spice program, providing I could find and enter the
data in the appropriate fields.

My question is this: can a devices modeling parameters be "manually"
gathered solely from its' datasheet or, would extraction software be
the only means? If so, could you direct me to an area of study?

These are devices I have datasheets for but no discernable spice data
yet:

TPDV640 Alternistor
DB4 Diac
BTB06-600T Triac

1.5K E68CA Bidirectional Diode (no datasheet as of yet)

Randy

 

Depends on how detailed the data sheet is, and how accurate you want the
model, but in general, yes you can make a good enough model from a data
sheet.

You need to understand the basic characteristics of the devices. So have
a look at description of the devices you want to model.

You want to have a go at modifying existing models of the same type. If
CM dont have them, there are some example diacs and trics in that other
Spice program


Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

Depending on realism required, yes, a comprehensive datasheet should
in theory give you enough to substitute parameters in an existing
model or subcircuit of CM.

None of my books (including AoE) gave me a definition of
'alternistor'. After 10 mins googling all I've been able to establish
is that it seems to be a triac that doesn't operate in quadrant IV. If
there are other distinctions, maybe someone can enlighten me please?

I'd have thought that was relatively easy to make as a CM macro, with
two back to back (suitably specified) diodes. Or even just *use* two
diodes in the circuit.

My approach would be substitution into one of CM's 54 triacs, after
examination of the data sheet. That said, I recall giving up on a
similar exercise a year or so ago, with a MOSFET I think, largely
because I couldn't find several of the specific CM parameters listed
explicitly in any manufacturer's data sheet. I suspect that will be
the problem with a triac too. Taking a look at the first of those 54,
the MAC15A6 I see this:

*400V 15A pkg:TO-220 2,3,1
..SUBCKT XMAC15A6 1 2 3
QN1 5 4 3 NOUT OFF
QN2 11 6 7 NOUT OFF
QP1 6 11 3 POUT OFF
QP2 4 5 7 POUT OFF
DF 4 5 DZ OFF
DR 6 11 DZ OFF
RF 4 6 40MEG
RT2 1 7 18.8M
RH 7 6 87.5
RGP 8 3 23.1
RG 2 8 11.5
RS 8 4 102
DN 9 2 DIN OFF
RN 9 3 41.6
GNN 6 7 9 3 15.2M
GNP 4 5 9 3 18.1M
DP 2 10 DIP OFF
RP 10 3 29.5
GP 7 6 10 3 10.3M
..MODEL DIN D (IS=45.8F)
..MODEL DIP D (IS=45.8F N=1.2)
..MODEL DZ D (IS=45.8F N=1.5 IBV=10U BV=400)
..MODEL POUT PNP (IS=45.8F BF=5 CJE=4.02N TF=38.2U)
..MODEL NOUT NPN (IS=45.8F BF=20 CJE=4.02N CJC=804P TF=2.55U)
..ENDS XMAC15A6

Maybe one of the professionals here can step you through how you would
change that 400V 15A TO-220 to your BTB06-600T?

I think they behave like diacs with greater power capability.

 

Bi-directional Diode - A plain piece of wire.

Kevin Aylward

http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.

 

Diacs are 'stateful' devices, like SCRs or TRIACs. When their avalanche
voltage is reached, they 'break over', and exhibit negative resistance.
They are often used to trigger triacs for this reason.

Diodes won't do this.

CM doesn't have a diac model, but here is a site that has some models:

http://users.skynet.be/hugocoolens/spice/power/

I haven't tried them out in CM yet.

--
Regards,
Robert Monsen

"Your Highness, I have no need of this hypothesis."
- Pierre Laplace (1749-1827), to Napoleon,
on why his works on celestial mechanics make no mention of God.

 

Thanks again for the direction,

I found this info on the Alternistor:

"A special chip offers the same performance as two thyristors
(SCRs) wired inverse parallel (back-to-back), providing better
turn-off behavior than a standard triac. An alternistor may be
triggered
from a blocking to conduction state for either polarity of
applied AC voltage with operating modes in Quadrants I, II,
and III.
This new chip construction provides two electrically separate
SCR structures, providing enhanced dv/dt characteristics while
retaining the advantages of a single-chip device."

This may be a key to modeling this device: "electrically seperate
SCRs", "wired inverse parallel" provided I can trigger them. The
circuit that contains these components is located at:
www.twelvemileroad.com/welder_control.html and is unusual indeed.

The bi-directional diode gave me pause too. If wired as configured in
the circuit, nothing will pass through, a complete "open". There has
to be more to it but, I can't find it.

Randy