Category: Hardware
Product Number: LT3494EDDB#TRMPBF, LT3494
hello,
I have the current schematic design:
I measure the circuit without load.
LT3494 is designed to output 18.4V (18V0 net on U21 pin 7).
In practice it outputs 22.5V. I measure 1.479V on the FB pin (instead of 1.225V).
Calculating Vout with Vfb=1.479V does give 22.5V.
With another board (same design), Vout=25V (Vfb=1.66V).
I understand, for the LT3494, a minimum load must be present to prevent the output voltage from drifting too high, but this is taken care of by the Shunt Control block.
Why is Vfb not equal to 1.225V?
thanks,
Gil