TL431: the output ripple(noise)with different producing area

max qin

Part Number: TL431

hi ,sir/madam:

I meet with the problem which use the some circuit with different producing area . one is from mexico ,another is from china ,but the have different output voltage ripple. the former is only 10mv ,the latter is above 50mv ,colud you please give me some news or information about this .

over 6 years ago

0 Marcoo Z over 6 years ago

TI__Mastermind 19570 points

Hi Max qin,

Can you show us the schematic?
Can you verify that the circuit is not oscillating?
What is the Cload on the TL431?

-Marcoo

0 max qin over 6 years ago in reply to Marcoo Z

Prodigy 40 points

Hi，marcoo:

thanks for your quick resoponse, The circuit as below which recommend in datasheet, please help me to check all the componet if it suitable ?

0 max qin over 6 years ago in reply to max qin

Prodigy 40 points

0 max qin over 6 years ago in reply to max qin

Prodigy 40 points

sorry forget the schecmatic.

0 Marcoo Z over 6 years ago in reply to max qin

TI__Mastermind 19570 points

Hi Max qin,

I have never seen a LC filter at the output of a tl431. Is there a particular reason for a the LC filter?
At lower frequencies the inductor will act like a short and the value of the C17 might cause instability. I would recommend to increase the value of C17 or decrease to a region where the TL431 is stable.

-Marcoo

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TL431: the output ripple(noise)with different producing area