I'd like to simulate the digital 74LVTxx chips with their analog characteristics. Packages like Multisim and OrCad only have the basic models (e.g. 74LS04N).
============= SPICE Model =================
.MODEL 74LSIC04 d_chip ( behaviour= "
+; 74LSIC04 Hex Inverter
+/inputs 1A 2A 3A 4A 5A 6A
+/outputs 1Y 2Y 3Y 4Y 5Y 6Y
+/module INV08
+/inputs A
+/outputs Y
+/table 2
+; A Y
+ L H
+ H L
+/delay 1
+; input output Rise time Fall time
+ A Y 15n 15n
+/endmodule
+/instance INV08 1A 1Y
+/instance INV08 2A 2Y
+/instance INV08 3A 3Y
+/instance INV08 4A 4Y
+/instance INV08 5A 5Y
+/instance INV08 6A 6Y
+")
============= Model template =================
a%p [%t1A?%t:d%t;1A
+ %t2A?%t:d%t;2A
...
+ %tVCC?%t:d%t;VCC
+ %tGND?%t:d%t;GND] %m
I went to NXP and downloaded the circa 1999 PSpice file holding a family of 74LVP models called lvtps.cir. Trying to import this into Multisim resulted in an unconnected spaghetti network. Editing a similar part with this *.cir in the DB editor led to many, many errors. OrCad has no idea what to do with it. Only Cadence PSpice could "simulate" the lvtps.cir file, but that doesn't help me add a 74LVTxx chip to a schematic.
LVT PSPICE MODELS
**************************************************************************
* LVTPS.CIR
* Low Voltage BiCMOS Logic
* Logic Products Group
* Philips Semiconductors
* 3/9/99
* Version 1.02
* Revision Comment: Subcircuits added for expansion of available LVT
* device simulations.
...
**************************************************************
* PACKAGE MODELS
.LIB "lvtpkps.s"
* SUBCIRCUIT MODELS
.LIB "subps.lib"
**************************************************************
* UNCOMMENT ONLY THE DEVICE MODEL FILE DESIRED
* NOMINAL, SLOW, AND FAST FAB PROCESS CORNERS
* NOMINAL PARAMETERS
.LIB "nomps.lib"
...
Question: How to simulate these 74LVTxx models?* Does this cir file need to be flattened by hand?
*Not asking for a software recommendation as I have a few.
Best Answer
I have previously only massaged Philips/NXP/Nexperia logic models from the HCT and LVC families, but took a stab at the LVT since you specifically requested the 74LVT04 in the question comments. It's a little more complicated than the other two, so I might have screwed something up in the process. With that disclaimer...below is the
74LVT04.libfile which simulates a single gate when calling a single instance of74LVT04. If a 74LVT1G04 existed it would be more equivalent to that (see 74LVC1G04 to see what I'm talking about). The "nominal parameters" fromnomps.libwere used. Also note that the package parasitics fromlvtpkps.sare not present here.You can also create a full chip 74LVT04D (SO14) by creating another subcircuit which calls 6 instances of the single gate subcircuit. Below is an example of this (untested). I didn't attempt it, but this is where you should manually add the package parasitics if you need that extra accuracy.
I don't use PSpice because all the cool kidz (yes, with a
Z) use LTspice. Therefore, below are some screenshots from LTspice which I took...while wearing my shades of course. I also included the code for the LTspice symbol (74LVT04.asyfile) I used.