LM5160A: ISOGND & GND Capacitor

Peter Martynenko

Part Number: LM5160A

In the isolated Fly-Buck application of the LM5160A, the example schematic from TI's datasheet (page 26) shows C3 as a 2200pF, 2000V capacitor between the ISOGND and GND.

What is the function of capacitor C3 and does it have a bearing on the VOUT ripple? Thanks.

over 1 year ago

0 Aurora Tie over 1 year ago

TI__Genius 17080 points

Hi Peter,

C3 can improve EMI and will not affect the output voltage ripple. Its withstand voltage is determined by the customer's system isolation voltage standard, which is generally greater than 1500V. Thanks.

Aurora

0 Peter Martynenko over 1 year ago in reply to Aurora Tie

Prodigy 10 points

Hi Aurora,

Thanks for clarifying the effect of C3. I suspected that it would have some higher order effect due to its small value, such as reduction in PCB's radiated and/or conducted emissions at F_sw harmonics. Thanks again.

Peter M.

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LM5160A: ISOGND & GND Capacitor