LT1073 9v to 3v step down converter

[hanshen]

I connect the circuit at above and solder it, but it just does not work. The value of sw2 is not step down but the lt1073. Does this mean it is damaged?

when i do the stimulation using ltspice, althought i connect the circuit at above. it still need to put a Ground at the negative terminal of batteries to ensure it works. it just does not work with only battery connected .

can some1 help me debug it?

 

[randell_xtian]

it is a buck converter, it should work like in that circuit.

---------- Post added at 15:18 ---------- Previous post was at 15:14 ----------

btw, thus the inductor has its true value? or even your voltage divider, it will dictate the output of this IC. output of the divider will feedback to that IC.

 

[Neuport]

I am also looking at using the LT1073 in a project. I noticed that in the step-up examples, the recommended component values in Table 1 of the spec sheet do not match the recommended component values in the example circuits. Maybe you have the same problem with the step-down configuration.

 

[murali_dece]

Hello friend, the circuit you are wired is good only thing i found is feedback network R1 & R2 which result in 6V output. for 3V output you have to modify your R1 as 557.6K and R2 as 40.2K. finally what about the inductor it is made by you or purchased it should be properly selected