Hi, every one, I’m William from Taiwan.
I follow the sorce file to rebuild the notecarrier PCB.
When test it yesterday, GPS can not get any signal.
Then, start to debug try to find something different from design or datasheet.
Here have some question about 3.3V.
By follow up the notecarrier schematic.
Plug in the USB we should have 3.3V by power management IC " TPS63021DSJR ".
But I got more than 3.3V almost 4.2V on pin-3.3V.
Here is racommond circuit of power management IC " TPS63021DSJR ".
looks at the pin-FB, is different than the first picture.
maybe that’s why didn’t get the reference voltage.
then, I check the GPS IC " BGA725L6E6327FTSA1 "
max voltage is 3.6V, but now is 4.2V
what could I do to make those right?
thank you all !!