Barracuda.....update(2)

[porkluvr]

my mistake

When i load the Barracuda!+TGT.asc and run simulation i take a message that says "could not open library file "FMMTA14.sub"
What i can do????
Best Regards

Whoops - that's because I neglected to include the FMMTA14.sub file with that little package. Here it is. Copy this text into a text editor and save it as:
C:\Program Files\LTC\SwCADIII\lib\sub\FMMTA14.sub (making any appropriate changes to the path name). That should do it.
************************************************** *******************
*Zetex FMMTA14 Spice Model v1.0 Last Revised 12/6/2002
*
.SUBCKT FMMTA14 1 2 3
* C B E
Q1 1 2 4 SUB38C
Q2 1 4 3 SUB38C 12.75
*
.MODEL SUB38C NPN IS=1.1E-14 ISE=7.1E-15 NF=1.012 NE=1.4758
+BF=220 IKF=.12 BR=15 IKR=.05 RE=1.3 RC=.5 RB=.3 VAF=150
+CJE=14.5E-12 CJC=4.14E-12 VJC=.515 MJC=.26 TF=1.15E-9 TR=75E-9
.ENDS FMMTA14
*
*$
*
* (c) 2005 Zetex Semiconductors plc
*
* The copyright in these models and the designs embodied belong
* to Zetex Semiconductors plc (" Zetex "). They are supplied
* free of charge by Zetex for the purpose of research and design
* and may be used or copied intact (including this notice) for
* that purpose only. All other rights are reserved. The models
* are believed accurate but no condition or warranty as to their
* merchantability or fitness for purpose is given and no liability
* in respect of any use is accepted by Zetex PLC, its distributors
* or agents.
*
* Zetex Semiconductors plc, Zetex Technology Park, Chadderton,
* Oldham, United Kingdom, OL9 9LL
************************************************** **********************

It produce very good pulses but now i have problem with the match of the pulses. You Know.... difference voltage (not symetrical at the 453, difference phase (180 degree reverse),etc. But never mind..... i will match it.

About non-symmetrical pulses: When you use the diode equalization trick with CD4538 or HC221, if you do not allow the "tpw" capacitor to recharge between pulses you will get short and long pulses instead of having all the same.
FOR INSTANCE: In Carl's Hammerhead, I increase the 330Ω resistor (R46A, in the July 2006 schematic) to 360Ω, because otherwise - when the secondary delay pot is set for shortest delay N3 and N4 may not be equal (in my simulation).

Alternatively, you can use seperate RC timing components for each channel if you want the shortest delay between each channel, but then your individual channels will probably have worse matching between their sample pulses.
Please show me your specific circuit if you are still having a problem

[Geo]

Hi porkluvr, thanks for the file.
I will try it tomorrow. I have the pcb from barracuda but i used a LM-555 at 780 Hz for Tx pulses....(110us), a bc-558 transistor to reverse the pulses and after it to a 2x 4538. The first has a delay of 30us and after it the second has a delay about 200us. I suply all this with 0...+12V so after the 4538 i use 2 transistors to convert the pulses to -5V....+5V. Until now all are OK. But when i connect the sample pulses to the "Fet switch" the pulse goes to -1....+2V so can't turn the Fets on and Off. I can't understand why????
I use 2N3819. I have similar problem if i connect the pin10 (out) of the 4538 direct to the Fets......
Any idea........
Regards

[Geo]

Again here. I tried the file and now the simulation works ok.
But very bad pulses (for me).
Very small pulse width (4.5us) and the second sample pulse is very near to the first pulse (about 20us).
I don't know if there is any reason to be so near the pulses at the underwater detectors.
Does anyone know it, so to tell me???
Regards

[porkluvr]

.... when i connect the sample pulses to the "Fet switch" the pulse goes to -1....+2V so can't turn the Fets on and Off. I can't understand why????
I use 2N3819. I have similar problem if i connect the pin10 (out) of the 4538 direct to the Fets......
Any idea........
Regards

Check your 2N3819 connections. There are differents 2N3819 pinouts used by different manufacturers. You probably assume SGD but actually have GSD, or vice-versa.

Also, 2N3819 is probably not the best choice for a 2N5485 substitute because VGS(off) is a little high.

[Alexismex]

Hello forum
Porkluvr I have revised the schematic in my post 45 is OK 100% I post the front end i use for the two channel .
BEST WISHES 2008

[Geo]

Hi Alex.
Maybe all your schematic to work fine, but when i simulate the out of 40106 direct to 2N5485 then the pulses are not good. Maybe 40106 have not the ability to direct load the 2N5485. The same problem i have now with the 4538. Alone are working perfect but when i connect to the 2N3819 the pulse it falls. Today i will connect a resistance in series and i believe to finish the problem.
Regards

[Geo]

Check your 2N3819 connections. There are differents 2N3819 pinouts used by different manufacturers. You probably assume SGD but actually have GSD, or vice-versa.

Also, 2N3819 is probably not the best choice for a 2N5485 substitute because VGS(off) is a little high.

Hi porkluvr.
The connections of 3819 are good. Today i will try to connect in series with gate a resistor (56.... 100k). If i will not solve the problem then i will change the 3819 with BF245B.
I will try it later. Now i have problem with the TV antenna and i must repair it (i can't hear my sons)
Regards

[porkluvr]

view the netlist?

Geo, I thought you were talking about real life problem with FET. My sims run well (except for not having enough control over Barracuda timing).

Your problem is very strange. Make sure the power supplies are uniformly labled, and correct attribute parameters set for digital parts. Remember that +5V and 5V would not be interpreted as the same net.

I have idea. Send me a copy of your netlist. Maybe I can analyze that. Like so: View > Spice Netlist, then CTL+A, CTL+C and paste into email. You can get my email from my profile information.

Sun's coming up soon, I better go.

[porkluvr]

O0ooh, one more thing, not that anybody is is interested: remember that you can 'do' many things with simulation models that are not generally accepted as good practice, such as, operating HC221 from a 10V supply.

Operating levels and 'Level shifting' parameters must be considered carefully and intelligently. The spice model for HC221 will probably not complain if you apply a virtual 10V supply, but the real thing will very likely go up in smoke.

Do not get complacent just because your simulation 'runs'.

[Geo]

Geo, I thought you were talking about real life problem with FET. My sims run well (except for not having enough control over Barracuda timing).

Your problem is very strange. Make sure the power supplies are uniformly labled, and correct attribute parameters set for digital parts. Remember that +5V and 5V would not be interpreted as the same net.

I have idea. Send me a copy of your netlist. Maybe I can analyze that. Like so: View > Spice Netlist, then CTL+A, CTL+C and paste into email. You can get my email from my profile information.

Sun's coming up soon, I better go.

Hi porkluvr. Sorry for late answer, but i am very busy this time. I play (when i have time) with your file so there is not reason to send it to you. I believe after 3...4 days to find the time to finish the detector. If this time i should be error again then i will make a schematic and i will email to you to run it to the simulator
Best regards and Happy New Year

[Geo]

Hi porkluvr.
I want to run the new schematic at the LTspice, but there is not the CD4538 in the add components for the sample. Can you make it and to send here to me, or if there is any other way to take it.
Regards

[porkluvr]

see the PI.zip

Hello Geo -

I'm Sorry you couldn't find what you need. Use the CD14538B symbol and model. Look at the Goldscan setup.jpg in the PI.zip file for some setup tips.

CD4000.lib.txt contains the model, and the CD4000 folder contains symbols.

Not all "4538" type devices are the same; some manufacturer add hysteresis to one input or another. For instance, ST's HCF4538 has hysteresis on both inputs, but has a more limited range of RC components that are acceptable, compared to, say, Fairchild CD4538, which has no hysteresis that I am aware of.

Motorola's contribution is MC14538, and the CD14538 is from Texas Instruments. The TI datasheet specifies hystereses on both inputs, but I absolutely cannot vouch for the accuracy of our CD14538b model. But it's all I have. The simulation model is good for avoiding stupid mistakes, but of course it is not guaranteed to provide a realistic prediction!!

Oh, and it runs pretty slow. I use the reset line to keep the oneshots disabled until the LM555 starts firing, because simulations seems to run a little faster that way. What I like about the Barracuda, was that the simulations are very fast compared to Goldscan or Hammerhead, for what it's worth.

Good luck, and let me know if you still need anything.

[Noemio]

what about a PIC?

Hi all,

if you wish i could send you a hex file for a PIC16F84 with outputs for fets and mosfet.
Just tell me wich ports of the microcontroller I should use (but there's no difference, just to have a nice PCB) and the timings you prefer.
Could be needed to add a couple of transistors to shift from +5 to +12 and, I think, ICL7660 could no need sync and run freely.
I am rather interested in Barracuda PI too.

[nick_f]

Hi All,

Since the Anchor Electronics web site is down, you can still check its previous content using the Internet Archive.
Here is a link to some reviews of the Barracuda: http://web.archive.org/web/200210092...com/field.html

Regards,
Nicolae

[hoppy1166]

CD4538 PSPICE

I'm a Newbie to this and all forums, I need to find the PSpice for the CD4538/MC14538.
Can someone help me out?