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need help in LM317 & LM337

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NicholasTok

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Hello everyone,

I have a schematic diagram here showing how to build a dual voltage supply of + and - 5V using LM317 & LM337, just to ask, what is the minimum and maximum range input voltage for this 2 IC chips?

i will be using a 9V battery, is it possible? and i would need to know the minimum input voltage in order to guage the performance

the schematic can be found inside this post



Regrades,
Nicholas Tok
 

The spec you are looking for is the Line Regulation. From the datasheet, Vin-Vout must be greater than 3V and less than 40V. For your 9V battery, this means that the regulation is not guaranteed to work when the batteries output voltage falls below 8V. (The 5V output plus the 3V minimum required by the Line Regulation. ) Therefore, new fresh 9V batteries will work. Older partially discharged ones will start to be marginal.
 

I would prefer call LM317 & LM337 "2 V" voltage drop regulator.
According my own experience, most LM317 & LM337 will work well when Vi - Vout = 2V if you are not so strict in line regulation performance.
 

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