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TPS84A20 SIMULTANEOUS SEQUENCING

Other Parts Discussed in Thread: TPS84A20

I have a question regarding simultaneous sequencing on the TPS84A20 where the output of one TPS84A20 tracks another one. I have been following the process that is recommended in the  TPS84A20 data sheet on page 24.   The recommendation is to connect the resistor network of R1 & R2 show in figure 40 to the output fo the power supply that need to be tracked.  You are to use equations 3 and 4 to calculate the values of R1 and R2. 

 In my case the scenario is a 5V rail being simultaneously tracked by a 1.1V rail.  Working through equations 3 and 4 in the data sheet the following values are calculated for R1 and R2.

Vout1

5.0

Vout2

3.3

R1

69,300

R2

15,400

VR1

4.1

VR2

0.9

My observation is that the voltage across R2 (VR2 in the table above) would be the voltage at SS/TR which is 0.9V in this example after power is applied and the system reaches steady state.  This is lower than the 1.4V threshold for SS/TR required for the PWRGD of the regulator to go active as stated in the TPS84A20 data sheet:

My question is how can the PWRGD of the regulator tracking the output of another regulator be used to enable another regulator when the voltage a SS/TR does not exceed the threshold required for PWRGD to go active?  In addition, if PWRGD does not go active will the regulator every go into regulation?

Thanks for your help.

Regards,

John