Mode, EN pin connection for TPS51396

krishna unnamatla

Hi,

I have made connection like the attached image. I'm generating 3v3 @3A. As per the Electrical specs and MODE voltage calculation this should work as the voltage levels are with in limit. Correct me if I'm wrong.

Can i connect EN to VCC or not? also as per SS connection the regulator should work at 1.5ms right?

regards,

krishna.

over 5 years ago

0 Gerold Dhanabalan - Online Design Tools over 5 years ago

TI__Genius 14455 points

Hi,

If VCC comes up automatically once VIN is applied, it might be ok. But some devices need EN for the VCC to come up. In such a case this will be stuck.

We will get back with more details shortly.

regards,

Gerold

0 Yuchang Zhang over 5 years ago in reply to Gerold Dhanabalan - Online Design Tools

TI__Mastermind 18510 points

Hi, En pin can’t connect to VCC, you need to connect to VIN with dividers as Gerold mentioned or with external signal control, SS should be floating or connected with external cap. I don’t see VCC cap. Must add it, refer to datasheet value.

FB resistor value, around 20K for lower resistor and then decide for upper one. One 47pf cap can be reserved and parallel with upper resistor.

Yuchang

0 krishna unnamatla over 5 years ago in reply to Yuchang Zhang

Prodigy 40 points

Hi,

VCC cap is got cut in the image. if i float SS pin then the timing will be 1.5ms? I have preliminary datasheet from June 2017. SS timing was not mentioned clearly in it.

Please can you confirm the mode setting correct or not?

I have 0.9V and 1.2V rails on the board with SS time of 1ms, can i pull up En to any of these voltages?

krishna.

0 Yuchang Zhang over 5 years ago in reply to krishna unnamatla

TI__Mastermind 18510 points

Hi, I see you send E-mail to me, please send your complete schematic to me as well, let’s discuss this by Email next week, this thread will be closed.

Yuchang

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Mode, EN pin connection for TPS51396