Homework done on LTspice IV. See attached .zip package. This TL071 TL081 macromodel supplied by Texas Instruments looks fine regarding gain-bandwidth product (not tested the slew-rate yet), but according to me it is definitely wrong regarding the current taken by the OpAmp supply pins. Would you check the .zip package on your side and tell me if you agree ?
Cheers,
Steph
Attachments
hi,
two big advantages of LTspice IV over Tina 7 T.I. is the ability to define new parts, and the ability to work using hierarchical design.
TL071_discrete.asc is the hand-made TL071 schematic, fitted with input/output ports for using it into a hierarchy. There is no ground.
TL071_discrete.asy is the symbol to be used if you want to insert a hand-made TL071 in your circuit.
TL071 in power amp.asc is an example of how to embed a TL071_discrete into a design. It makes the top-level schematic easy to read.
When the main schematic is open (TL071 in power amp), it is possible to open the low-level schematic (TL071_discrete) by right-clicking on the TL071 symbol. You then get a multi-window workspace, with both the high-level, and the low-level, at transistor level. Under LTspice IV "run simulation", all the voltages and currents of the low-level circuit can be probed provided some options are duly activated into the control panel. As explained in page 34 of the LTspiceUserGuide, those options are "Save Subcircuit Node Voltages" and "Save Subcircuit Device Currents".
P.S. #1
The file named "TL071 discrete test alone" is not part of the hierarchy explained here. It is a stand-alone file made to test the hand-made TL071 circuitry, in a x10 gain configuration, fed by +15V / -15V power supplies, plus a 1 kHz generator.
P.S #2
A remark for European DIYers : under LTspice IV, one must ban the commas in the values. One must use the decimal point. A 4,7k resistor must be entered as 4700 or 4.7k, and nothing else.
P.S. #3
The name of a sub-schematic must be identical to the name of the symbol supposed to represent it.
Here, it is "TL071_discrete.asc" and "TL071_discrete.asy".
The names cannot contain spaces characters.
This is the reason why I have used underscores in the names.
This is explained in page 32 in the LTspiceUserGuide.
P.S. #4
If somebody could explain to me how fine tune the TL071 symbol for making it visually more appealing, that would be very kind. I would like to edit a full custom symbol, getting rid of the "default" rectangle.
See attached .zip file.
Cheers,
Steph
two big advantages of LTspice IV over Tina 7 T.I. is the ability to define new parts, and the ability to work using hierarchical design.
TL071_discrete.asc is the hand-made TL071 schematic, fitted with input/output ports for using it into a hierarchy. There is no ground.
TL071_discrete.asy is the symbol to be used if you want to insert a hand-made TL071 in your circuit.
TL071 in power amp.asc is an example of how to embed a TL071_discrete into a design. It makes the top-level schematic easy to read.
When the main schematic is open (TL071 in power amp), it is possible to open the low-level schematic (TL071_discrete) by right-clicking on the TL071 symbol. You then get a multi-window workspace, with both the high-level, and the low-level, at transistor level. Under LTspice IV "run simulation", all the voltages and currents of the low-level circuit can be probed provided some options are duly activated into the control panel. As explained in page 34 of the LTspiceUserGuide, those options are "Save Subcircuit Node Voltages" and "Save Subcircuit Device Currents".
P.S. #1
The file named "TL071 discrete test alone" is not part of the hierarchy explained here. It is a stand-alone file made to test the hand-made TL071 circuitry, in a x10 gain configuration, fed by +15V / -15V power supplies, plus a 1 kHz generator.
P.S #2
A remark for European DIYers : under LTspice IV, one must ban the commas in the values. One must use the decimal point. A 4,7k resistor must be entered as 4700 or 4.7k, and nothing else.
P.S. #3
The name of a sub-schematic must be identical to the name of the symbol supposed to represent it.
Here, it is "TL071_discrete.asc" and "TL071_discrete.asy".
The names cannot contain spaces characters.
This is the reason why I have used underscores in the names.
This is explained in page 32 in the LTspiceUserGuide.
P.S. #4
If somebody could explain to me how fine tune the TL071 symbol for making it visually more appealing, that would be very kind. I would like to edit a full custom symbol, getting rid of the "default" rectangle.
See attached .zip file.
Cheers,
Steph
Attachments
The positive and negative inputs can simply be identified by a + or - inside the symbol next to the connection point (right click on text and change "justification"). Output can be shortened to Out. Pos_supply and Neg_supply can be shortened to V+, V-, Vcc, Vdd, etc.
What is that square around it?
The symbol can be shortened lengthwise I think. I believe a stubbier (but not fat) triangle will be more aesthetic. I think the offset pins could be put somewhere inside the symbol instead of on the edge and that would be more aesthetic as well (that is, if you intend to add the offset pins).
- keantoken
What is that square around it?
The symbol can be shortened lengthwise I think. I believe a stubbier (but not fat) triangle will be more aesthetic. I think the offset pins could be put somewhere inside the symbol instead of on the edge and that would be more aesthetic as well (that is, if you intend to add the offset pins).
- keantoken
I still don't know how to get rid of the square around the symbol. The square comes upon telling LTspice to generate a symbol for the TL071_discrete circuit. How do I take an existing beautiful standardized opamp symbol (like the LM158 on Yahoo LTspice group) and tell LTspice to use it for the TL071_discrete subcircuit ? Are you telling me that the solution is to rename pins, in the TL071_discrete model ? But wait a minute .... what other symbol do you intend to use ? I'm still nowhere. See attached .zip files.
I haven't messed with this a lot, and I don't know anything about how LTSpice recognizes which model to put on which symbol. I'm sure the yahoo group would be more than happy to help you out.
In the attribute window you can open in the symbol editor, there is one field that tells LTSpice which model to use for the symbol. If you want to copy a symbol, you could probably open it in the symbol editor and then change this value. That is the extent of my knowledge.
- keantoken
In the attribute window you can open in the symbol editor, there is one field that tells LTSpice which model to use for the symbol. If you want to copy a symbol, you could probably open it in the symbol editor and then change this value. That is the extent of my knowledge.
- keantoken
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