When RUN pin voltage = 0V, output voltage is 28V which is Vin

Question

Hi ADI team, 
 I use LTC3769HFE#PBF in my circuit board. 
 
 When RUN pin voltage = 3V, output voltage is 50V which is OK. 
 However, when RUN pin voltage = 0V, output voltage is 28V which is Vin. 
 Is that normal for LTC3769HFE#PBF ? 
 Thanks~

Brian1201 · Accepted Answer

Shiba said: However, when RUN pin voltage = 0V, output voltage is 28V which is Vin. 
 Is that normal for LTC3769HFE#PBF ? 
 It's normal, because the Q3 internal diode from S to D is forward biased and allows current to flow from In to out even with Gate turned off. 
 Brian)

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When RUN pin voltage = 0V, output voltage is 28V which is Vin