Hi,

I'm trying to figure out either how to install the TL07x family of models (that I have) into LT Spice, OR use one of the generic ones that are "close enough". I'm new to LT Spice. Thanks.

 

Hi,

I'm trying to figure out either how to install the TL07x family of models (that I have) into LT Spice, OR use one of the generic ones that are "close enough". I'm new to LT Spice. Thanks.

What version of LTspice?
Where did you obtain the models?

 

I have used and designed thousands of audio circuits that used TL071, TL072 and TL074 opamps. None ever failed.
The circuits were designed for using a single positive supply or designed for using a dual polarity supply.
Since the circuits worked and tested perfectly then a simulation was not needed.

Simply keep the input voltage 4V away from the negative supply voltage to avoid the "Opamp Phase Inversion" problem with them.

 

What version of LTspice?
Where did you obtain the models?

whatever the latest is, just installed it. I got models from TI.

 

I have used and designed thousands of audio circuits that used TL071, TL072 and TL074 opamps. None ever failed.
The circuits were designed for using a single positive supply or designed for using a dual polarity supply.
Since the circuits worked and tested perfectly then a simulation was not needed.

Simply keep the input voltage 4V away from the negative supply voltage to avoid the "Opamp Phase Inversion" problem with them.

so then using a generic or ideal op amp in the circuit is fine, right? I’d prefer that and just use whatever the library has.

 

so then using a generic or ideal op amp in the circuit is fine, right? I’d prefer that and just use whatever the library has.

No, I don't recommend that. Use a TL072 model.
There are design constraints that exist in the TL072 that do not exist in the generic universal opamps.

 

A simulation might not show the Opamp Phase Inversion Problem and usually never shows it overloaded and burning up.

 

A simulation might not show the Opamp Phase Inversion Problem and usually never shows it overloaded and burning up.

Shows phase inversion but won't burn up.

 

Connect a 4 ohms load to see if it burns up with a 1A output.

The new datasheet for the TL07xH version shows a max supply of +42V and -42V and NO phase inversion if the inputs are 1.5V more positive than the negative supply.
The TL07xH is in a case that is surface-mount only. It produces much more noise than the original version.

 

Connect a 4 ohms load to see if it burns up with a 1A output.

Doesn't burn up.
But the output drops to 44mv.

 

Doesn't burn up.
But the output drops to 44mv.

Good. The simulation has the spec'd current-limiting.
44mV/4 ohms= 11mA. The power supply of the TL072 is 10V total then it heats with 110mW which is warm, not hot.

 

Good. The simulation has the spec'd current-limiting.
44mV/4 ohms= 11mA. The power supply of the TL072 is 10V total then it heats with 110mW which is warm, not hot.

Yup...11ma.

 

whatever the latest is, just installed it. I got models from TI.

Can you share for student like as TI072 model file ?
Thank you in advance

Umesh

 

Please read the 2017 Texas Instruments datasheet for the TL072. The 2021 version is confusing with the new TL072H added:

1) We talked about its "Opamp Phase Inversion" problem earlier in this thread. Your -5V input becomes less than 4V more positive than its negative supply.

2) It is an opamp, not a power amplifier. Its specs show a minimum load of 2000 ohms. Your 4 ohms load is VERY close to a dead short.