REF1930AIDDCT overshoot exceed 10%

user6261387

Prodigy 50 points

Other Parts Discussed in Thread: REF1930

REF1930 electric circuit as follows:

when power on, Vbias 1.5V overshoot exceed 10%,the same PCB another REF1930 is normal,why is that?

over 4 years ago

0 Marcoo Z over 4 years ago

TI__Mastermind 19570 points

Hi,

The REF20's internal circuitry, not including output buffers, is not fully active until ~2V. This means that the output will follow the input until ~2V which is the overshoot you measured. After 2V the internal circuitry is on and the op amps take over and regulate were possible.

0 user6261387 over 4 years ago in reply to Marcoo Z

Prodigy 50 points

Hi,thanks for your reply

but ,why some REF1930 Vbias 1.5V is no overshoot?

0 Marcoo Z over 4 years ago in reply to user6261387

TI__Mastermind 19570 points

This can be due to changes in the input/output cap or a change in the input voltage ramp. This screenshot shows a slower ramp time that can occur with a slower input voltage or larger output cap.

Power management

Power management forum

REF1930AIDDCT overshoot exceed 10%