TMS320F28335: Power sequencing OPAMPS

Rajesh,

            It is entirely up to you how you want to implement the sequencing as long as every condition laid out in the datasheet is met. BTW, TPS767D301 is also a LDO. By using it, you will be able to bring down the component count in your board. Below post has more information on sequencing: 

https://e2e.ti.com/support/microcontrollers/c2000-microcontrollers-group/c2000/f/c2000-microcontrollers-forum/391204/tms320f28335-example-circuit-power-sequencing-3-3v-and-1-9v

Rajesh,

   Your understanding is incorrect. Please see page 48 of www.ti.com/lit/SPRS439 (7.9.2 Power Sequencing):

Note that there is also a requirement for the -XRS pin:

It is important you meet all the requirements in section 7.9.2. As stated earlier, I cannot mandate how exactly you implement these requirements. However, in order to reduce the component count (and hence reduce cost and make board routing easy), you could consider a part like TPS767D301. It has dual regulators with 1A rating for each. Each regulator also has an enable pin, so you could sense the 1.9v output and use that to determine exactly when you want to turn on the 3.3v output. If you want to use a couple of OP-AMPs, that is fine as well.

OK sir