LM4651/LM4652 class D amps

[soongsc]

Hi,

I've done an inductor or two but certainly not an expert on them.

Caps, no, I was pulling your chain 🙂 I just cut those out of whatever's too close.

It would be a good thread though.

Regards,
Chris

Me too.😀

 

[soongsc]

Re: Inductance calculator

Hi Soongsc,

Do you have any inductance calculator? I would like to roll my own inductor from magnet wire.

Thanks.

The one that BWRX posted is what I used once. The first one I did was sort of a guess from an existing one, and it came out good for prototyping.

try this out: http://www.oz.net/~coilgun/mark2/inductorsim.htm

 

[Ipanema]

Thanks.
😀

 

[PierreG]

PCB Group buy

A PCB group buy would be nice.
Somebody want to start it?

 

[PierreG]

Nobody interesred?

 

[davide1980]

HI! I can supply you some pcbs, professionally made, double layer with soldermask and silkscreening! Based on gerber files directly from national. I had 11 of them, now I have 5 of them, but I can make others!
I can sell them for 23 $ us dollars. If interested, contact me at animalepesante@katamail.com ! I don't read the forum every day...
bye bye!
Davide

 

[Nisbeth]

Apologies for bumping this old thread 🙂

I finally got around to assembling my boards, but looking at the datasheet for the LM4651 gets me a little confused: The resistors Rv1 and Rv2 are 750R on the schematic and 750k in the BoM. Similarly, the 12V zeners are rated 1W on the schematic and 500mW in the BoM. Which of these are correct?


/U.

 

[SpittinLLama]

750 ohms is correct. Those resistors are just there to limit current on the 12V zeners. The 12V zeners are found by using 22V (worst case) - 12V = 10V/750 ohms = 13mA * 12V = 160mW. So 500mW is just fine. You can use 500mW and up and not have a problem. Even 250mW if they make such things. The resistor value in the BOM is a typo. BTW, get these ICs while you can, they are on lifetime buy and will not be around forever.

-SL

 

[Nisbeth]

That's what I needed to know, thanks 🙂


/U.

 

[Rodo]

Hi. I found a very usefull doc written in excel in National´s website. It´s for calculate almost any component variations for LM4651/LM4652. I hope it help somebody here that deals with LM4651/LM4652.

 

[Rodo]

Hi. I found a very usefull doc written in excel in National´s website. It´s for calculate almost any component variations for LM4651/LM4652.

You could find document "ClassD_Design_Guide13.xls" in link below:
http://www.national.com/appinfo/audio/files/ClassD_Design_Guide13.xls