lm337 tweaks

[mrdave45]

Im trying to tweak a negative 5v supply. I used a zener (probably a 3v7) to tie the output to 5 v. Anyway, in order to keep my dacs negative supplys to 10v difference i want to lower(raise?) the -5v which is currently -5.14 to -4.74 to match the -14.74 measured on my super reg.

Anyway to do this by adjusting the resistor to fine tune rather than the diode.

Had a play round withthe formula given in the data sheet but as R2 is now a diode its not that helpful. (although i tried raising the adj R slightly.

Any ideas?

Ta.

 

[martin clark]

If that's for a TDA1541 you might find it easier to tweak the Sreg down to -15.1v by increasing its gain very slightly - try adding 10k or so in paralell with the smaller of its voltage-setting resistors.