AnsweredAssumed Answered

May QN908x VDD power from external DC-DC circuits?

Question asked by Yuan Te Liu on Feb 25, 2019
Latest reply on Mar 1, 2019 by Estephania Martinez

From AN11996 "QN908x Hardware Design Considerations" (Rev.1.3 April, 2018)
It described the way to design QN908x power using its internal DC-DC converter to provide 1.3V VDD power to QN908x core, RF, and Analog block. I have some questions to this

 

(1) Due to the mechanical dimension limitation, we cannot employ any components higher than 0.8mm, therefore, we cannot use the recommended inductors. Actually, it is very hard to find 10uH inductors with such low profile meeting our requirements.  May I provide VDD power directly from external circuit (eg. external DC-DC controller with higher switching frequency with small inductance)? If it is positive, any cares should be noted?

(2) If the answer of (1) is positive, may you teach me the power (current) to be provided ?

(3) Continued to question (2), If I do not use RF block, how much current may be reduced? May I simply ground (or not connected) the VDD2 pin if I do not use RF ?

Regards  

Outcomes