anybody tried a LM4780? - Page 2 - diyAudio
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Old 16th August 2003, 05:44 AM   #11
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nice 27 pin to220 case.

"what's the deal with 3 differenct cap values on the rails? "
-distance i think. i think the 1000 uF cap is more for supply decoupling, and the 10uf and 100nf caps would be located much closer to the chip then the 1000uF.

there is a section in the pdf http://cache.national.com/ds/LM/LM4780.pdf

about this. application info - supply bypassing. page 16 of 24.

the chip is listed as ready for samples. there is a demo PCB layout in the pdf file.
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Old 16th August 2003, 11:42 AM   #12
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Wonder if anyone would make the eval board...however it still seems simple enuf for a p2p job...though a bit messier...prefer a protoboard this time round...
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Old 16th August 2003, 09:15 PM   #13
ukram is offline ukram  Finland
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Nice looking layout in the eval board. 2.7 ohm resistor (RG)between signal ground and power ground. RG is not shown in schematic ??? I could sell clones of this PCB, if there is enough interest...
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Old 17th August 2003, 01:32 AM   #14
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I'll take one...but can you make the parts through hole?? Or maybe you can sell the boards without the Chip only...meanoing the parts are already soldered...I don't have the equipment to play with SMD stuff...
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Old 19th August 2003, 07:47 PM   #15
ukram is offline ukram  Finland
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It is TO220 package, so no SMD stuff required. But i cannot do cheap two sided boards, so i have to redesign the PCB as single sided.

I did not get the samples directly from National (i did get samples direct from TI). They said i must ask local distributor. From the company list i find for example Farnell. Wish me luck ordering samples from there...
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Old 25th August 2003, 03:38 AM   #16
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got my samples today... p2p I DON"T THINK SO!!! the chip is abit bigger than the LM38**'s but there is twice as many pins, they are thinner, and smaller together... anyway designing a PCB? would I be able to bridge the amp into a 4ohm speaker with +-25volt rails? I need 80 - 120watts from +-25 volt rails.. hmm.. lol
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Old 25th August 2003, 09:28 AM   #17
Bricolo is offline Bricolo  France
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what about the 4700 and 4701?
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Old 25th August 2003, 10:33 AM   #18
ir is offline ir  New Zealand
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got me one of the LM4732 chips the other day, 50W per channel.

i'll just do like i did with the stereo20 and 40 and build them on veroboard! yeah it's not pretty, but it works
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Old 25th August 2003, 10:47 AM   #19
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Yeah...I'm pretty interested in a board without SMD stuff...and perhaps configurable configurations...like 120W mono or 60W Stereo...
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Old 25th August 2003, 11:25 AM   #20
deandob is offline deandob  Australia
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Default Using a LM4765

I'm using a LM4765 - sister chip to the LM4780 with 30Wpc for a whole home audio system where I use these as local amps for each room controlled by a touchscreen. When I prototyped these up last year using 1000uF power supply caps I was very pleased with the sound quality, it was able to reproduce dynamics better than my much more expensive DIY discrete MOSFET amp. The design uses the non inverting mode, when I tried inverting I could not stabilise the amp although I suspect trying this on breadboard was not optimal.

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