LMZ10503 power sequencing

Sumit Gupta

Other Parts Discussed in Thread: LMZ10503

I have 2 lmz10503 modules, one for 1V supply and 2nd for 1.8 V supply. I need to power on 1V 1st and then power on 1.8V. From the datasheet, it seems the enable pin on lmz10503 needs 1.23V to activate the enable function. How can I drive the enable pin from the 1V power rail ?

Sumit

over 12 years ago

0 Akshay Mehta over 12 years ago

TI__Genius 15810 points

I've forwarded your query to the right application engineer.

0 YangZhang over 12 years ago in reply to Akshay Mehta

TI__Genius 11085 points

Sumit:

One way I can think of is to add a divider between VIN and Vout1 (the 1V output) and connect the middle point of the divider to the EN of the 2nd module. The division ratio is set such that When Vout1 is 0V, the EN2 voltage is below 1.23V and when Vout1 = 1V, the EN2 voltage is above 1.23V.

regards,

Yang

0 Sumit Gupta over 12 years ago in reply to YangZhang

Prodigy 20 points

Hi Yang/Akshay

Thanks for the reply. Will vout1 be at 0V initially ? or will it be floating. Because if its not at 0V in the beginning then the divider will always turn on the EN for vout2.

Also wont there be a risk of supply noise from VIN to get into vout1 ?

Sumit

Power management

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LMZ10503 power sequencing