LT3066EMSE-3.3

[zhivko]

I try to use fixed 3.3V variant of LT3066 to get 3.3V on output from 45V input. I use: LT3066EMSE-3.3. Problem is that I get Vin to Vout.
My schematics is as follows (attachment).

Datasheet is here: http://www.analog.com/media/en/technical-documentation/data-sheets/3066fa.pdf


Can somebody tell what is wrong with current schematics that I get 12V on OUT_1 and OUT_2 pins if I connect 12 V to IN_1 and IN_2 pins?

Thank you and regards,
Zhivko

[pyroesp]

You need to connect the sense wire to the output.
Also, best use a resistor on PWRGD. There's a MOSFET to GND, see the system block diagram in the datasheet.

[zhivko]

Thank you very much - you are correct.
This is schematics (part of datasheet):

[tsman]

What sort of current requirements do you have for the 3.3V output? 48V in and 3.3V out with this linear regulator will mean it gets incredibly hot even with fairly low current output. Look at page 20 of the datasheet and put in your numbers to work out what temperature rise to expect and what your maximum current output will be before it hits the maximum rated temperature.

[zhivko]

Max current that needs to be provided is 300mA, but this is when ESP32 chip is initializing or sending data. Otherwise most of the time is below 100mA.
Yesterday I made required changes (connected sense to Vout) and didn't finger test if chip gets hot. But will do that and report back.
regards and thank you very much for your comment!.

[zhivko]

If I don't use PWRGD - is it OK to let it float? I guess it is OUTPUT and used by some power monitoring chip that supervises this power chip?