BQ51013B: tantalum caps for rect and out

German Baranov

Intellectual 660 points

Part Number: BQ51013B

Hi!

Design recommendations for bq51013b assume using ceramic caps for Cout and Crect.

Are there any principal objections against using tantalum caps of proper voltage and capacity on these positions?

My problem is that 1206 X7R 10uF 16V are whistling (producing sound) while being used there, which I can't afford.

It's quite possible that cap from another manufacturer and even from different lot will not whistle, but I'd prefer to get rid of guessing.

Thanks a lot

over 6 years ago

0 Bill Johns over 6 years ago

TI__Guru* 75786 points

Hello

Crect application of tantalum caps would work, this is the rectifier bridge output.

Cout application has some risk, it is a regulated output and more sensitive to high freq noise.

The Whistling is probably due to Acoustic Noise produced by Mult Layer Ceramic Capacitor (MLCC). The noise will be produced as voltage changes on the device, the operating freq is beyond audible range. The comm packets are send every 250ms and this would be in the audio range, may be generating the noise. If the noise is comm packets it is probably coming from Crect. The regulated output should be very stable, no change is voltage and Cout is less likely to generate noise.

The Acoustic Noise behavior of MLCC devices has been seen before and a number of articles are available that describe it and possible solutions, see below:

https://www.edn.com/design/components-and-packaging/4364020/Reduce-acoustic-noise-from-capacitors

https://e2e.ti.com/blogs_/b/powerhouse/archive/2016/08/09/how-to-reduce-acoustic-noise-of-mlccs-in-power-applications

https://www.murata.com/en-us/products/capacitor/mlcc/apps/notepc

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BQ51013B: tantalum caps for rect and out