"Random" Circuit Needed.

Started by Jim Thompson in sci.electronics.design6 years ago 149 replies

For a simulation situation I need a random number generator with a twist... What I need to simulate is a "random" selection of one-of-16...

For a simulation situation I need a random number generator with a twist... What I need to simulate is a "random" selection of one-of-16 outputs. Clock "speed" is 12.5kHz ;-) Built of 74HCxx parts is preferred... I have a full ensemble of those device in my PSpice library. Thanks in advance. ...Jim Thompson -- | James E.Thompson ...


Oscillator buffer

Started by o pere o in sci.electronics.design9 years ago 38 replies

The thread related to large signal PSpice models and an emitter follower comes from the following problem: I have an oscillator that should...

The thread related to large signal PSpice models and an emitter follower comes from the following problem: I have an oscillator that should drive a digital part of the system. In short, what is the best way to achieve this? My first attempt has been a common base Colpitts oscillator that gives a signal riding on the +Vcc rail. This has been AC coupled to a 74AC gate biased to the poin...


What would you call it?

Started by Jim Thompson in sci.electronics.design5 years ago 7 replies

What would you call it? I've developed a simple-minded subcircuit for use with NOISE analyses in Spice/PSpice/LTspice such that... o It...

What would you call it? I've developed a simple-minded subcircuit for use with NOISE analyses in Spice/PSpice/LTspice such that... o It passes DC at whatever RDC you set o It jumps to gmin/2 at some corner you set, FCO o It's a flat impedance at gmin for the rest of the spectrum I need a name for this PART ;-) (I'll post the subcircuit as soon as I decide on a name.) ...


Stepping multiple parameters in a simulation

Started by Jim Thompson in sci.electronics.design8 years ago

A question presented on the LTspice list by John Woodgate prompted my answer, which may be of interest to other...

A question presented on the LTspice list by John Woodgate prompted my answer, which may be of interest to other LTspice/PSpice/whatever users: Here's an extreme example of multi-parameter stepping... In this example "Case" was stepped 1, 2, 3, 4 to get all the combinations needed by the test (IBIS model generation :-


OT: DDE Psipce

Started by Martin Riddle in sci.electronics.design6 years ago 4 replies

Jim, My fresh VM of WIN7 64bit already has an association for .sch files. I points to schdpl32.exe, MS schedual+ I think you need to scan...

Jim, My fresh VM of WIN7 64bit already has an association for .sch files. I points to schdpl32.exe, MS schedual+ I think you need to scan the registry for these extensions: .sch .slb .mvl And delete the entries. You'll find them in HKEY_CLASSES_ROOT and HKEY_CURRENT USER You might want to delete all the keys tha have psched.exe in them too. Then reinstall Pspice. My dem...


LM1117 model

Started by John Larkin in sci.electronics.design5 years ago 5 replies

http://www.ti.com/product/LM1117/toolssoftware If I download the "LM1117 Adjustable Unencrypted PSpice Transient Model", how do I use that in...

http://www.ti.com/product/LM1117/toolssoftware If I download the "LM1117 Adjustable Unencrypted PSpice Transient Model", how do I use that in LT Spice? If I plop the file in the current sim folder, and .LIB name it on the schematic, how do I create a corresponding schematic symbol? I want to see how it behaves with various load capacitors, like a polymer aluminum in parallel with a lot o...


OT: Equation Solving

Started by Jim Thompson in sci.electronics.design5 years ago

In my development of a generalized OpAmp model with independent setting of GBW, Slew Rate and Input Transition Width I found myself hung on...

In my development of a generalized OpAmp model with independent setting of GBW, Slew Rate and Input Transition Width I found myself hung on solving the transfer function shown in green... for the value of VB at the right-most zero crossing. My in-PSpice Newton Solver barfed. Then I lit on the idea of using my new Most_Positive segme


LTspice Question

Started by Jim Thompson in sci.electronics.design9 years ago 1 reply

Suppose, in PSpice, I have a behavioral current source that "quits" unless it has at least 0.5V across it... GDC_I1 N_1 N_2 VALUE...

Suppose, in PSpice, I have a behavioral current source that "quits" unless it has at least 0.5V across it... GDC_I1 N_1 N_2 VALUE {(1+TANH(2.2/0.1*(V(N_1,N_2)-0.5)))/2*1mA} Can LTspice understand that line "as is", or must it be changed? If it must be changed, what is the proper syntax? Thanks! ...Jim Thompson -- | James E.Thompson, CTO ...


Faux MOSFET... Behavioral Modeling

Started by Jim Thompson in sci.electronics.design8 years ago 5 replies

For sometime now I have been trying to build a behavioral model of logic gates that was consistent with real-world behavior when mixed into an...

For sometime now I have been trying to build a behavioral model of logic gates that was consistent with real-world behavior when mixed into an Analog environment. (Existing logic models, such as those in PSpice and LTspice are state machines and do not behave properly when used for Analog applications, such as when you build a crystal oscillator around a 74HCU04.) So I now invite you to ...


Ping Jeff L: Hide Taskbar Tabs

Started by Jim Thompson in sci.electronics.design6 years ago 7 replies

Jeff, PSpice Schematics puts a pile of tabs in the taskbar most of which are useless "management" and message windows. I've run across...

Jeff, PSpice Schematics puts a pile of tabs in the taskbar most of which are useless "management" and message windows. I've run across "Clicky Gone" as a tool to hide such creatures. What would you recommend? Thanks! ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations ...


OT: Archiving a Sub-Directory, Preserving PathsI

Started by Jim Thompson in sci.electronics.design5 years ago 5 replies

I have a directory tree: C: PSpice DeviceLib X-Fab XB06 NewLib I want to...

I have a directory tree: C: PSpice DeviceLib X-Fab XB06 NewLib I want to just zip the contents of directory NewLib (and its subdirectories), but maintain the path information in the archive all the way back to C: (without including all the preceding directory's contents). The client would then unzip a complete tree match...


AN: Function Generator Subcircuit

Started by Jim Thompson in sci.electronics.design5 years ago 3 replies

See FuncGen.zip on the Device Models & Subcircuits Page of my website. Updated today to be a general-usage subcircuit on most...

See FuncGen.zip on the Device Models & Subcircuits Page of my website. Updated today to be a general-usage subcircuit on most simulators... previously was only PSpice/OrCAD compatible. Features square, triangle and sine-wave outputs, voltage-controlled (VCO), selectable frequency and control voltage ranges. ...Jim Thompson -- | James E.Thomps...


Any TopSpice Users Here?

Started by Jim Thompson in sci.electronics.design6 years ago 3 replies

Any TopSpice Users Here? I have an OpAmp model out there that runs fine on PSpice, LTspice, HSpice, etc., but balks on TopSpice. The error...

Any TopSpice Users Here? I have an OpAmp model out there that runs fine on PSpice, LTspice, HSpice, etc., but balks on TopSpice. The error report, from the TopSpice output file is: GSw_Sw3 N_22 -VB VALUE {((TANH(9.485/0.1*(V(SHUTDOWN, + GND)-0.5))+1)/2)*(V(N_22, -VB)/1)} 0*ERROR*: mismatched parentheses in above expression check result= -1 0*ERROR*: loading VALUE be...


LTspice model for DB3 DIAC

Started by P E Schoen in sci.electronics.design2 years ago 4 replies

I was trying to design a simple voltage relay in LTspice and I wanted to = use=20 a DIAC, but I had a hard time finding a model that worked....

I was trying to design a simple voltage relay in LTspice and I wanted to = use=20 a DIAC, but I had a hard time finding a model that worked. Finally I = found=20 the following in an obscure Japanese or Chinese website=20 http://bbs.dianyuan.com/topic/111118: * PSpice Model Editor - Version 9.2 *$ ********** *SRC=3DDB3; 32V 2A *DIAC *=B8=C4=B1=E4DZ=B5=C4BV=BF=C9=D2=D4=B8=C4=B1=E4Vbo ...


LTspice: X-Axis Variable

Started by Jim Thompson in sci.electronics.design2 years ago 10 replies

In LTspice, is there a way to change the X-Axis variable? In PSpice I can do a PWL simulation, then change the X-Axis variable (in Probe) to...

In LTspice, is there a way to change the X-Axis variable? In PSpice I can do a PWL simulation, then change the X-Axis variable (in Probe) to be a voltage within the circuit, thus displaying hysteresis. I can't find a similar function in LTspice. ...Jim Thompson -- | James E.Thompson | mens | | Analog In...


Relay coil has inductive reactance proportional to sqrt(f)

Started by motie in sci.electronics.design5 years ago 28 replies

I assume this is because of eddy current losses. Does anybody know how to model sqrt(f) as an impedance in Pspice? I'm guessing a series...

I assume this is because of eddy current losses. Does anybody know how to model sqrt(f) as an impedance in Pspice? I'm guessing a series combination of parallel LR's, but I don't know how to calculate the values. http://i232.photobucket.com/albums/ee69/motie42/relay%20impedance_zpsnnfxifla.jpg Red trace is measured impedance vs frequency. Black dotted trace is 10*sqrt(f), a nearly perfect ...


PING: Aylward or other Spice Expert

Started by Jim Thompson in sci.electronics.design4 years ago 4 replies

PING: Aylward or other Spice Expert... Bringing up a 0.18u/0.35u Vanguard process, building up the PSpice model libraries. Discovered...

PING: Aylward or other Spice Expert... Bringing up a 0.18u/0.35u Vanguard process, building up the PSpice model libraries. Discovered strangeness: ALL devices have HDIF=0.2u, except "native" NMOS, which has HDIF=0.02u!! I thought this might simply be a typo, but that HDIF value is repeated in each of the corner parameter statements. 0.02u seems awfully small to me. Can this be...


TUTORIAL - Example 2, Using Femm to Calculate Component Values of Simple buried Stripline configured like a coax to use in LTspice/PSpice

Started by RobertMacy in sci.electronics.design6 years ago

These anlayse work at 2.5GHz in FR4 type PCB material for those of us who want to drive ?? or an antenna = Bluetooth, Wifi, zigbee, or GPS...

These anlayse work at 2.5GHz in FR4 type PCB material for those of us who want to drive ?? or an antenna = Bluetooth, Wifi, zigbee, or GPS antenna module and want to see how much a 'longer than desirable coax' run detriorates the NF of the Receiver. The skin effect is in there, but I did NOT want to make this a 'broadband model' Skin effect issimply at 2.5GHz. Boradband Model is res...


OT: Mouse Action Reassignments.

Started by Jim Thompson in sci.electronics.design7 years ago 16 replies

Is there a program that will reassign mouse actions? I'd like the following (Window-specific to PSpice Schematics)... Mouse wheel forward...

Is there a program that will reassign mouse actions? I'd like the following (Window-specific to PSpice Schematics)... Mouse wheel forward one click, send , , Mouse wheel reverse one click, send , , ...Jim Thompson -- | James E.Thompson | mens | | Analog I