REF5050: Spice model don´t work when in negative shunt configuration.

Leonardo Cunha

Part Number: REF5050

Dear technical support,

I simulated a similar circuit to the one described in the voltage reference design document of TI for negative voltage connected in shunt configuration. But, TINA TI doesn't show the values correctly in the output. Instead of 5V, I´m getting 1.77V on the output when I run a DC analysis -> Calculate nodal voltage.
I think that spice model was not developed for this type of configuration.
Could someone review spice model to model shunt configuration ?

Best Regards,
Leonardo Cunha

slim174a.tsc

over 1 year ago

0 Trailokya Rai over 1 year ago

TI__Genius 11356 points

Hi Leo

I will simulate the circuit and get back to you on Monday.

Regards

Trailokya

0 Trailokya Rai over 1 year ago in reply to Trailokya Rai

TI__Genius 11356 points

Hi Leo

It is not working in TINA . I will ask the team to correct it.

You can simulate shunt behavior in PSPICE Model. REF5050_PSPICE_AIO.zip

Regards

Trailokya

0 Leonardo Cunha over 1 year ago in reply to Trailokya Rai

Prodigy 30 points

Hi Trailokya

Thanks for the feedback! Alright, but...if I can test it using TINA I would be very glad.

Regards,
Leonardo

0 Trailokya Rai over 1 year ago in reply to Leonardo Cunha

TI__Genius 11356 points

Hi Leonardo

Please see below circuit. It is working for 5V shunt.

REF50 Shunt.TSC

Regards

Trailokya

0 Leonardo Cunha over 1 year ago in reply to Trailokya Rai

Prodigy 30 points

Hi Trailokya

I'm away from the my laptop now, because I've been traveling for work, but as soon as I get back I will test the circuit that you uploaded.

Regards,
Leonardo

0 Leonardo Cunha over 1 year ago in reply to Leonardo Cunha

Prodigy 30 points

Hi Trailokya

Yeah, your circuit is working in a positive shunt configuration ! However, I connected this same model of REF5050 in a negative shunt configuration and the voltage on output is - 1.77V. So, the problem continue.

Regards,

Leonardo

REF5050 Negative Shunt Configuration.TSC

0 Trailokya Rai over 1 year ago in reply to Leonardo Cunha

TI__Genius 11356 points

Hi Leonardo

Give us some time we will update it.

Regards

Trailokya

+1 Trailokya Rai over 1 year ago in reply to Trailokya Rai

TI__Genius 11356 points

Hi Leonardo

There is some convergence issue with GND current in the model when GND is getting -ve voltage. VIN is not getting sufficient current if the GND is operating <=6mA current. I'd sufggest to use VIN = -11 and it will work nicely.

Regards

Trailokya

0 Leonardo Cunha over 1 year ago in reply to Trailokya Rai

Prodigy 30 points

Hi Traiolokya

With this test, I understand that the model is working, although of it is working outside the limits of input voltage range as per described on datasheet.
For my purpose, the problem is solved !
Thank you very much !!!

Regards,
Leonardo

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REF5050: Spice model don´t work when in negative shunt configuration.