LME49810 PSpice Model available at TI

jackinnj · 25th September 2012, 08:15 PM

Texas Instruments put the model on their website a couple days ago - a zip file on the product page, but not in their index of models and ref designs:

Speaker Amplifier and Modulator - Mid/High-Power Amplifier - LME49810 - TI.com

I don't see it on the LTSpice yahoo group library yet.

linuxguru · 26th September 2012, 05:13 AM

The PSpice model is encrypted - also includes an LM1876 model, similarly encrypted. Is there any way to generate a generic unencrypted Spice .subckt from these encrypted models?

Ouroboros · 26th September 2012, 07:08 AM

The TINA ref design from the site works, once you have re-edited the shockingly badly drawn schematic to cure some nets that aren't properly connected. The ref design is very crude so I haven't yet checked how closely the model matches the real data sheets.
Are TI getting kids on 'work experience' schemes to do these ref designs?

Ouroboros · 26th September 2012, 07:09 AM

BTW, the TINA SPICE model is also encrypted, so you can't back-engineer an LT-SPICE model from it.

jackinnj · 26th September 2012, 12:33 PM

Quote:

Originally Posted by Ouroboros

BTW, the TINA SPICE model is also encrypted, so you can't back-engineer an LT-SPICE model from it.

If you get enough of the behavior you can back-engineer it.

I will bug TI about it - the same issue came up with respect to the model for the LM3886.

I pointed out an error on one of the TI datasheets -- an update for a product that's been in production for over 20 years -- they have yet to correct the error. Ergo, I am not optimistic that they are going to change the encryption of the models.

Ouroboros · 26th September 2012, 03:44 PM

Having had a closer look at the TINA reference design, it's a load of rubbish! The compensation cap is set to 1uF! When I set it to 22pF, the FR doesn't change. also the output transistor quiescent current isn't changing when I alter the bias voltage. If I get some spare time tomorrow I will use the SPICE model to build up the data sheet ref circuit from scratch in TINA and see how it simulates. TI aren't doing too well with releasing valid SPICE models of the Nat-Semi audio chips so far!!

jackinnj · 04:02 PM

I think that they could hire a couple of English majors from SMU to edit the technical notes coming out of the Far East.

I just have the TI version of TINA and it doesn't allow you to import other models, but you can download the reference design.

Ouroboros · 27th September 2012, 06:59 AM

But of course there's nothing to stop you copying the LM49810 block from the ref design and pasting it into a new design.
Also with the free version of TINA, you can copy functional blocks that don't exist in that version from other TINA designs on the web onto a dummy schematic from which you can copy and paste them into your own design. The free version of TINA will simulate properly using them. It's just that those blocks aren't available on the menu bar in the free version.

Ouroboros · 28th September 2012, 10:49 AM

Well, I tried using the model to build up a sim of what is basically figure1 in the Nat Semi data sheet for the 49810. Still no use at all. The SPICE sim amplifies, yes, but the 'biasP' and 'biasM' inputs sem to have no effect, neither does the value of the compensation cap. The only thing that seems to work is the operation of the MUTE pin!

Putting out SPICE models that are misleading, or in this case, of no use whatsoever is worse than not having the model in the first place.

panson_hk · 24th April 2013, 04:26 AM

I tried the TINA 49810 example today. There is no current from Bias_P to Bias_M. The model is useless.

25th September 2012, 08:15 PM	#1
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	LME49810 PSpice Model available at TI Texas Instruments put the model on their website a couple days ago - a zip file on the product page, but not in their index of models and ref designs: Speaker Amplifier and Modulator - Mid/High-Power Amplifier - LME49810 - TI.com I don't see it on the LTSpice yahoo group library yet.

26th September 2012, 03:56 PM	#7
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	I think that they could hire a couple of English majors from SMU to edit the technical notes coming out of the Far East. I just have the TI version of TINA and it doesn't allow you to import other models, but you can download the reference design. Last edited by jackinnj; 26th September 2012 at 04:02 PM.

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26th September 2012, 05:13 AM	#2
linuxguru diyAudio Member Join Date: Sep 2007	The PSpice model is encrypted - also includes an LM1876 model, similarly encrypted. Is there any way to generate a generic unencrypted Spice .subckt from these encrypted models?

26th September 2012, 07:08 AM	#3
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	The TINA ref design from the site works, once you have re-edited the shockingly badly drawn schematic to cure some nets that aren't properly connected. The ref design is very crude so I haven't yet checked how closely the model matches the real data sheets. Are TI getting kids on 'work experience' schemes to do these ref designs?

26th September 2012, 07:09 AM	#4
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	BTW, the TINA SPICE model is also encrypted, so you can't back-engineer an LT-SPICE model from it.

26th September 2012, 03:44 PM	#6
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Having had a closer look at the TINA reference design, it's a load of rubbish! The compensation cap is set to 1uF! When I set it to 22pF, the FR doesn't change. also the output transistor quiescent current isn't changing when I alter the bias voltage. If I get some spare time tomorrow I will use the SPICE model to build up the data sheet ref circuit from scratch in TINA and see how it simulates. TI aren't doing too well with releasing valid SPICE models of the Nat-Semi audio chips so far!!

27th September 2012, 06:59 AM	#8
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	But of course there's nothing to stop you copying the LM49810 block from the ref design and pasting it into a new design. Also with the free version of TINA, you can copy functional blocks that don't exist in that version from other TINA designs on the web onto a dummy schematic from which you can copy and paste them into your own design. The free version of TINA will simulate properly using them. It's just that those blocks aren't available on the menu bar in the free version.

28th September 2012, 10:49 AM	#9
Ouroboros diyAudio Member Join Date: Dec 2003 Location: Nottingham UK	Well, I tried using the model to build up a sim of what is basically figure1 in the Nat Semi data sheet for the 49810. Still no use at all. The SPICE sim amplifies, yes, but the 'biasP' and 'biasM' inputs sem to have no effect, neither does the value of the compensation cap. The only thing that seems to work is the operation of the MUTE pin! Putting out SPICE models that are misleading, or in this case, of no use whatsoever is worse than not having the model in the first place.

24th April 2013, 04:26 AM	#10
panson_hk diyAudio Member Join Date: Aug 2005 Blog Entries: 10	I tried the TINA 49810 example today. There is no current from Bias_P to Bias_M. The model is useless.