Trouble with LME49724 spice model.

Richard Meidl

Other Parts Discussed in Thread: LME49724, TINA-TI

Hello,

I am trying to run a TINA simulation on a single-ended to differential conversion using the LME49724. I keep getting errors on nodes that are not part of my circuit. I have simplified my circuit to figure 51 on the LME49724 data sheet. The last error said, "Irregular circuit" Node 63 Component/Terminals: .U1 UCM_NET1. What do I need to change in order to run this circuit. I used the macro from the TINA library and also the .TSM file from TI's web site. Both models had the same errors. Please advise.

Thanks,

Rich

over 10 years ago

0 Hooman Hashemi over 10 years ago

TI__Mastermind 22825 points

Hi Rich,

I was able to take the Reference Design from the LME49724 Product Folder and edit and run both AC and Transient Response:

Here is the TINA-TI file for above:

LME49724 Closed Loop Gain (added 100k to ground on diff input) Hooman 5_13_15.TSC

Note:

I added R2, R3 (100k to ground on each leg of the differential input) in case that causes any issues with your simulation in the future (you don't need it for the present setup). With simulation, you may sometimes have to ensure that the differential source has a "path" to ground (again, in this case you don't need these two resistors).

Regards,

Hooman

0 Richard Meidl over 10 years ago in reply to Hooman Hashemi

Intellectual 370 points

Hello Hooman,
Thank you for your help. I was able to get the simulation to work. There were a couple of things that I had to change in my original simulation. I had only used cap coupling off of the VCM pin. The data sheet says that it is internally biased, but I had to have a DC path in order for the simulation to run. Also, I was using a dual supply, +15 V and -15V. I tied the enable pin to ground since it is more than 2.35 Volts above VEE. I ended up connecting it to VCC to get the simulation to run.
Anyway, your model helped me to get the simulation to work. Thank you for your help.
Best regards,
Rich

0 Hooman Hashemi over 10 years ago in reply to Richard Meidl

TI__Mastermind 22825 points

Hi Rich,

Glad to hear you were able to get things running.

Regards,

Hooman

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Trouble with LME49724 spice model.