LM3406 Vin disturbance testing with inductor noise

PHILIP HSU

Expert 1900 points

Other Parts Discussed in Thread: LM3406

Hi Sir,.

customer got the LM3406 Vin disturbance testing with inductor noise, 3406 switching 130-150KHz

the disturbance source is three each : a. 1-10KHz :Ipp 6, 10KHz-100KHz : 6-5.4log(f/10)*

b. 0.05-1KHz : 0.2Vp-p , 10K-100KHz: 2Vpp

c. 2-10KHz 0.5Vp-p , 60KHz-100KHz 5Vp-p

then got inductor noise then adjuge to fail,

How`s the way reduce the ear heared nosie please ?

over 10 years ago

0 JohnTucker over 10 years ago

TI__Guru**** 191445 points

i cannot comment specifically on LM3406, but if you inject frequencies in the audio band especially in the 1 to 10 kHz region, you may excite the inductor to produce audible noise. Some inductors are less prone to this, What inductor are you using?

0 PHILIP HSU over 10 years ago in reply to JohnTucker

Expert 1900 points

John

there was SMD Shielded inductor with normal status, but strange noise once Vin inject testing,,..

desides, did you share diffenetial filter or small ac signal for dc balancing way for this solution ?

desire

Power management

Power management forum

LM3406 Vin disturbance testing with inductor noise