TINA/Spice/LM3481: LM3481 synchronization Duty,max?

user5080343

Prodigy 20 points

Part Number: LM3481
Other Parts Discussed in Thread: TINA-TI

Tool/software: TINA-TI or Spice Models

I am using LM3481 for boost application,

syn pin to ground resistor is 200K ohm,

open loop test duty, max about 86%( spec= 85%),

but I try to add external clock = 150KHz (3V, duty=20%) signal at syn pin,

duty, max about 79%

Why is the duty,max going down?

thanks,

Burgess

over 6 years ago

0 Garrett Roecker over 6 years ago

TI__Mastermind 21720 points

Hello Burgess,

The engineer supporting this device is out of the office. He will return next Tuesday.

Thanks,

Garrett

0 user5080343 over 6 years ago in reply to Garrett Roecker

Prodigy 20 points

ok, thanks :D

0 Youhao Xi over 6 years ago in reply to user5080343

TI__Guru* 76815 points

Hi User,

Sorry for the delay. I need to check this with our designer to see if this is the case for the real circuit. Hopefully we can get an answer for you tomorrow.

Thanks,
Youhao Xi, Applications Engineering

0 Youhao Xi over 6 years ago in reply to Youhao Xi

TI__Guru* 76815 points

Hi User,

I have gotten confirmation from our design team that the sync pulse width should not affect the max duty cycle. It seems to be an issue of spice model. As you may know, model always have some small flaws when comparing with the real part. Not every function can be 100% accurately modeled owing to model linearization and behavioral representation.

Thanks,
Youhao

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TINA/Spice/LM3481: LM3481 synchronization Duty,max?