LM5164-Q1: Behavior with OPEN Pin

Kurumi Hasegawa

Expert 6641 points

Part Number: LM5164-Q1
Other Parts Discussed in Thread: LM5146

Hi team,

What would be expected behavior with the following condition?

Would it operate, or would there be no output?

EN/UVLO open
RON open
FB open

I tried to see the behavior using the simulation but it does not work (error was popped up).

I'd appreciate it if you could give me some possible outcomes.

Best regards,

Kurumi Hasegawa

over 3 years ago

0 Victor Yu over 3 years ago

TI__Expert 4371 points

Hi Kurumi，

What's the main purpose of this question？ I think it can't be simulated in Pspice or Simplis， because we don't know the charge distribution on those floating pin in real world.

In my opinion, there will be no output since there isn't a EN voltage. When Ven<1.1V, this device will be in shutdown mode with all function disabled. And LM5146 doesn't have a internal current source to pull up Ven. So, when PIN EN is floating, this device will mostly in shutdown mode, the states of PIN RON and PIN FB are meaningless here.

If it is an important biz case, I can test on demo next week.

BR,

Victor

0 Kurumi Hasegawa over 3 years ago in reply to Victor Yu

TI__Expert 6641 points

Hi Victor,

Thank you for your comment. The customer is considering the case when open/short happens, like poor soldering.

Also, sorry for the confusion. I meant that when PIN EN/RON/FB open separately. For example when the PIN EN and FB are connected correctly but PIN RON is open.

From your comments, I guess when EN is open there might be no output. Could you give us some predictions on PIN RON and FB?

Best regards,

Kurumi Hasegawa