On/Off pin on National LM2675

Newton

Expert 1125 points

Other Parts Discussed in Thread: LM2675

Does the On/Off pin on LM2675 part need to be connected?

If it's left floating, is part enabled or disabled?

I couldn't find any information on this in the data sheet.

over 11 years ago

0 Mark Green over 11 years ago

Intellectual 660 points

Just had a quick look on the datasheet:

The apps schematic on p9 and the layout on p22 show this pin as floating.

Hope this helps.

0 Denislav Petkov over 11 years ago in reply to Mark Green

TI__Mastermind 18940 points

To add to what Mark Green mentioned, if you look at the block diagram in figure 1 (page 7), the EN pin has an internal pull-up current source which gets clamped at 7V. This indicates that the part will be normally ON if the EN pin is left floating.

Regards,

Denislav

0 Constantine Laskov over 8 years ago in reply to Denislav Petkov

Prodigy 50 points

Looking at the datasheet and could not find any references about you are talking above, check by himself : lib.chipdip.ru/.../DOC001164761.pdf.
As a result, if somebody could clearly explain what should I do for switching off the device - connect pin to GND or to V_in/V_out.
P.S.: I don't see any mentioned pull up resistors on p.8 fig.17.

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On/Off pin on National LM2675