LM2611: LM2611 RC decision

Thomas Yang55737

Part Number: LM2611

Tool/software:

Hi Team,

Two questions need your help:

1) LM2611 Vout=(1+Rf1/Rf2)*Vfb， here Vfb = -1.23, so Vout = -.4.84V, why the datasheet reference design show it is -5V.

2) In customer case, Vin = 9V, Vout = -9V, could you suggest the RC value or the reference dsign for this target.

Thanks

0 Nini Zhong 6 hours ago

Hi Thomas,

1. Vfb=1.23V, Vout=(1+29.4/10)*1.23=5V; If VOUT=9V, change the Rfb1 to 77.8kΩ;

2.Capacitor keep the same.

0 Thomas Yang55737 4 hours ago in reply to Nini Zhong

Hi Nini

Thanks for feedback, Vout=(1+29.4/10)*1.23= 4.84V, not 5V, is there any misunderstanding in my side?

-Thomas

0 Nini Zhong 4 hours ago in reply to Thomas Yang55737

Hi Thomas,

Please use this equation, and set the Vfb1 to 30kΩ or higher resistance to set the output voltage.

0 Thomas Yang55737 3 hours ago in reply to Nini Zhong

Thanks Nini, it is clear now, let's close the ticket.

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