Setting Up A Darlington Transistor In LTspice

Thread Starter

newbie2019

Joined Apr 5, 2019
95
Hi:

I downloaded an LTspicemodel for TIP121 and TIP127 darlingtons. I have a "pdarlington" and an "ndarlington" symbol (although they look ugly). In the Component
Attribute Editor I placed an "X" in the prefix value "QNNN" in the Instance Name
value, an "X" for the corresponding "Vis", the Model name in the SpiceModel
value and an "X" in the corresonding "Vis".

When I try to simulate a circuit with one of these models, I get the following
error message."Could not open the TIP121 sub file." I placed the ".lib" files
in the sub folder.

I must have messed up somewhere. Any advice would be appreciated.

Thanks.
 

Attachments

Last edited:

wayneh

Joined Sep 9, 2010
16,114
Hi:

I downloaded an LTspicemodel for TIP121 and TIP127 darlingtons. I have a "pdarlington" and an "ndarlington" symbol (although they look ugly). In the Component
Attribute Editor I placed an "X" in the prefix value "QNNN" in the Instance Name
value, an "X" for the corresponding "Vis", the Model name in the SpiceModel
value and an "X" in the corresonding "Vis".

When I try to simulate a circuit with one of these models, I get the following
error message."Could not open the TIP121 sub file." I placed the ".lib" files
in the sub folder.

I must have messed up somewhere. Any advice would be appreciated.

Thanks.
Your include statement asks for TIP121.sub but the file name is TIP121.lib. They need to match!
 

wayneh

Joined Sep 9, 2010
16,114
Hi:

My secret is out.

I think this circuit isn't right somehow. Vbe is like 60 nanovolts rather than 1.2 to 1.4 volts.
Maybe I don't understand darlingtons.
I've attached a modified version of your circuit. I don't have the symbol for the TIP121 so I used the TIP142 included with LTspice. I see a normal Vbe.
See if that works and then try changing out to the TIP121.
 

Attachments

Thread Starter

newbie2019

Joined Apr 5, 2019
95
I've attached a modified version of your circuit. I don't have the symbol for the TIP121 so I used the TIP142 included with LTspice. I see a normal Vbe.
See if that works and then try changing out to the TIP121.
Thanks Wayne. I'm getting 60 nV on the base.
 
Top