TPS27081A application

ASB

Other Parts Discussed in Thread: TPS27081A, TPS27082L

I have an external power source which is connected to TPS27081. When the power is applied to the board it should enable TPS27081A. The MCU1 IO will turn the power off by pulling EN down. Once the En is pull down it will be tri-stated and the power will come with RC constant of the +5V_Ext. Is the right approach or do I have to make some adjustment to this ? do u see any issues with this? Please let me know.

over 12 years ago

0 Ron Michallick over 12 years ago

TI__Guru**** 167286 points

ASB,

Let see if I understand the desired result. Output turns on some time after external 5V turns on. MCU1 can pull enable low to turn 5V internal off then after redoing the power up delay the 5V internal will turn back on.

Be sure that the MCU1 I/O line is tolerant of voltage on the pin when the MCU is unpowered.
Due to the slow rising enable signal, the TPS27082L would be a better solution in same package and pin out.

0 ASB over 12 years ago in reply to Ron Michallick

Intellectual 415 points

are these two parts pin compatible?

0 Ron Michallick over 12 years ago in reply to ASB

TI__Guru**** 167286 points

ASB,

Yes, they are same except. The "R2" resistor is internal fixed. The enable has a buffer to turn on cleaner when the enable voltage hits the turn on threshold. It also has a faster turn off.

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TPS27081A application