Any good driver transistor that have LTSpice model available

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#21
rsavas said:
use bob's 2sa1381 and 2sc3503 models first. these were originally NEC parts now discontinued by them, fairchild, a second source is the ksa/ksc pairs that are still in production.
Click to expand...
I must be blind!!! I did not see that. They should be the same.

Thanks, Now I have all the models for the OPS.

It seems to me that the model of OPS is not as critical as the IPS and VAS because they are all EF. The distortion with OPS is more about the crossover distortion. Seems like it's more important to look at the distortion comparison of different bias current, different emitter resistor than beta and fT as long as you have fT over 30MHz, beta over 75!!!

Attached is my OPS schematic. I am going to change the output transistor to MJL. If I just use some transistor that is close to 2SC2837 and 2SA1186, it seems like it should be close enough.
 

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#22
Alan0354 said:
I must be blind!!! I did not see that. They should be the same.

Thanks, Now I have all the models for the OPS.

It seems to me that the model of OPS is not as critical as the IPS and VAS because they are all EF. The distortion with OPS is more about the crossover distortion. Seems like it's more important to look at the distortion comparison of different bias current, different emitter resistor than beta and fT as long as you have fT over 30MHz, beta over 75!!!
Click to expand...

The driver ft will make a difference when choosing the local decoupling for
the pre/driver in an EF3 , or when driving the OPS with a super fast CFA stage.

The ksc3503/a1381 - high Ft driver - njw0302/0281 combo for
pre/driver/output , simulates right up to an IPS that has >1Kv/us slew.

I noticed this combo when trying for the max slewrate "award" 😀.

OS
 
#23
ostripper said:
The driver ft will make a difference when choosing the local decoupling for the pre/driver in an EF3 , or when driving the OPS with a super fast CFA stage.

The ksc3503/a1381 - high Ft driver - njw0302/0281 combo for
pre/driver/output , simulates right up to an IPS that has >1Kv/us slew.

I noticed this combo when trying for the max slewrate "award" 😀.

OS
Click to expand...
What is local decoupling? I don't know the term. I am not using CFA just to be safe.
I king of think the first EF is more important as it buffer the VAS. KSA and KSC having high fT and beta should really help. After that, seems like the 2nd and the power transistor is not as important.

Thanks
The drive stage is set up for standard TO-247 pin out, Should I use MJW1302/3281 as pre driver? You don't happen to have the model for MJW? It seems to be very close to MJL1302 and 3281.

I can't wait to sent this OPS board out.
 
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#24
Alan0354 said:
What is local decoupling? I don't know the term. I am not using CFA just to be safe.
I king of think the first EF is more important as it buffer the VAS. KSA and KSC having high fT and beta should really help. After that, seems like the 2nd and the power transistor is not as important.

Thanks
The drive stage is set up for standard TO-247 pin out, Should I use MJW1302/3281 as pre driver? You don't happen to have the model for MJW? It seems to be very close to MJL1302 and 3281.

I can't wait to sent this OPS board out.
Click to expand...

"local decoupling" is what you did to your predriver stage.
Another example would be the .01u-.1u right at op-amp Vcc/vdd pins.

OS
 
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