Vout3 of ADP1031 not used

Question

Hello. 
 I have a question. Please tell me. 
 If VOUT3 is not used, can VOUT3, FB3 and SW3 be left unconnected? 
 I think the ADP1032 is recommended, but I am considering whether it can be replaced because there are no parts. 
 Best Regards.

jeco · Accepted Answer

Hi baggio, 
 
 The inverter/VOUT3 on the ADP1031 can be disable by: 
 
 removing the inductor connected to SW3, SW3 should be floating. 
 VOUT3 should be tied to GND. 
 FB3 must be supplied within this range 0.8V < VFB3 < 0.8V +10% in reference to VOUT3/GND to disable the SW3 from turning on.
 
 The voltage on FB3 can be generated from VOUT2 through resistor dividers. For example, for 5V VOUT2 &ndash; use 10kohm across the FB3 and VOUT3/GND. Use 51.5kohm resistor across VOUT2 and FB3. This resistor divider combination will give 0.818V on FB3 in reference to VOUT3/GND.

This will not only disable the switching of the SW3 but also retain the PWRGD functionality. 
 Thanks, 
 Jefferson

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Vout3 of ADP1031 not used

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