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am3871 Power-Up Sequence：Can I power-up 1.8V first,then power-up 3.3V?

zuobing huang
Intellectual 300 points
Other Parts Discussed in Thread: AM3871
am3871 hard design:
in the am3871 data sheet 7.2.8:  " The 3.3 V supplies must never be more than 2 V above the 1.8 V ."
 
Can I power-up 1.8V first,then power-up 3.3V? I can add a diode between 1.8V and 3.3V. The anode of the diode link to 1.8V, the kathode of the diode link to 3.3v.
The V Delta between 1.8V and 3.3V  will form -0.7v to 1.5V (3.3v-1.8v). 
  • 0
    TI__Mastermind 43875 points

    As long as you follow the rules in section 7.2.8 of the datasheet you can implement this in whatever way is simplest for you. Be aware of any current supply requirements for each supply when 'stealing' from other supplies with diodes though.

    If you look at figure 7-1 you can see that time (1) has no bounds, so yes, 1.8V can go high before 3.3V

    BR,

    Steve