PMIC PF3001: value of Vin (min), when Vout is 3.3V

[Yuri]

Hello,

   PMIC PF3000 Datasheet contains the following comments regarding voltage drop

for the SW2:

  The higher output voltages available depend on the voltage drop in the conduction path as given

by the following equation: (VSW2IN - VSW2) = ISW2* (DCR of Inductor +RONSW2P + PCB trace

resistance).

 The similar statement, which allows to estimate minimal input voltage, is also for the SW3;

but there is no such equation for the SW1. What are considerations for the SW1?    

https://www.nxp.com/docs/en/data-sheet/PF3000.pdf 

Regards,

Yuri.

[guoweisun]

Hi

In set down regulator equation: (VSW2IN - VSW2) = ISW2* (DCR of Inductor +RONSW2P + PCB trace

resistance).

The conditions of entry into force that equation is in the bypass mode the 100% duty cycle under VIN very near with VOUT.

This equation can be used in each set down regulator same with SW1/2/3 if Vout is very near with VIN.

[Yuri]

Hello, guoweisun 

 The equation 

(VSW2IN - VSW2) = ISW2* (DCR of Inductor +RONSW2P + PCB trace resistance)

relates to SW2.

  Is the same correct for the SW1 ?

Regards,

Yuri.

[guoweisun · Accepted solution]

Sure,same with SW1.