LM13700 OTA - SPICE transistor terminals ?

[mw]

This is probably an easy question for the Spice people, but I want to
make 100% sure. I can't be sure which pin is which because the pins
aren't identified on my simulator's schematic symbol. They are shown as
additional pins connected to an opamp shape, yet there are no labels.

On the datasheet there are terminals are named:

Amp Bias Input
Diode Bias
Buffer Input
Buffer Output

In the model supplied by National Semi, there is an order defined as
follows:

* Amplifier Bias Input
* | Diode Bias
* | | Positive Input
* | | | Negative Input
* | | | | Output
* | | | | | Negative power supply
* | | | | | | Buffer Input
* | | | | | | | Buffer Output
* | | | | | | | | Positive power supply
* | | | | | | | | |
..SUBCKT LM13700/NS 1 2 3 4 5 6 7 8 11

.... and further into the model there are these definitions:

Q1 24 32 31 QX1
Q2 23 3 31 QX2
Q3 11 7 30 QZ
Q4 11 30 8 QY

My simulator's symbol shows the terminals as unmarked pins, but opening
the "Amplifier9" model symbol I see 8 pins labeled. Plus I can click on
"pin order" and see the order they are listed. The 4 pins of interest are:

Q1 : model pin 6, pin order 6th
Q2 : model pin 7, pin order 7th
Q3 : model pin 8, pin order 8th
Q4 : model pin 4, pin order 9th

I can't understand how it should be hooked up. The pin order in the
symbol editor is different from the SPICE model. I have made some
guesses and the part appears to work OK in the circuit, but where in
this mess are the pins clearly defined?

mw

 

[Jim Thompson]

On Sat, 05 Aug 2006 12:50:58 GMT, mw <mw@avoidspam.com> wrote:

This is probably an easy question for the Spice people, but I want to
make 100% sure. I can't be sure which pin is which because the pins
aren't identified on my simulator's schematic symbol. They are shown as
additional pins connected to an opamp shape, yet there are no labels.

On the datasheet there are terminals are named:

Amp Bias Input
Diode Bias
Buffer Input
Buffer Output

In the model supplied by National Semi, there is an order defined as
follows:

This is called the "declaration".....

* Amplifier Bias Input
* | Diode Bias
* | | Positive Input
* | | | Negative Input
* | | | | Output
* | | | | | Negative power supply
* | | | | | | Buffer Input
* | | | | | | | Buffer Output
* | | | | | | | | Positive power supply
* | | | | | | | | |
.SUBCKT LM13700/NS 1 2 3 4 5 6 7 8 11

... and further into the model there are these definitions:

Q1 24 32 31 QX1
Q2 23 3 31 QX2
Q3 11 7 30 QZ
Q4 11 30 8 QY

My simulator's symbol shows the terminals as unmarked pins, but opening
the "Amplifier9" model symbol I see 8 pins labeled. Plus I can click on
"pin order" and see the order they are listed. The 4 pins of interest are:

Q1 : model pin 6, pin order 6th
Q2 : model pin 7, pin order 7th
Q3 : model pin 8, pin order 8th
Q4 : model pin 4, pin order 9th

I can't understand how it should be hooked up. The pin order in the
symbol editor is different from the SPICE model. I have made some
guesses and the part appears to work OK in the circuit, but where in
this mess are the pins clearly defined?

mw

When used in your circuit, the "instantiation", the pin ORDER as shown
in the netlist must match the pin ORDER as given in the "declaration".

BUT they don't have to have the same node names.

Clear as mud but it covers the ground ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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