lm4780 project

laki101

Member
2009-12-24 12:47 pm
thinking of making a amp using the lm4780 in bridge/parallel (I am asking you which would you recomend) config like in the datasheet http://www.national.com/ds/LM/LM4780.pdf page 5/6
now I am not sure how to wire it so could you please just write me which pin do i connect and where actually I am just not sure do I need to all V+ to +rail etc. or is just one enough and what are the NC pins?

and does any one have any experience with this chip
 
thinking of making a amp using the lm4780 in bridge/parallel (I am asking you which would you recomend) config like in the datasheet http://www.national.com/ds/LM/LM4780.pdf page 5/6
now I am not sure how to wire it so could you please just write me which pin do i connect and where actually I am just not sure do I need to all V+ to +rail etc. or is just one enough and what are the NC pins?

and does any one have any experience with this chip

The 4780 is two identical 3886 chips in one package. Some pins are shared and others aren't. Yes, you should wire up multiple voltage pins not just one of each. NC = not connected. These can even be snipped off... if you're sure you have the right ones.

As said, try a simple amp first and learn how it works and what various necessary and optional components do and how to wire them all up.
 

erky01

Member
2008-09-29 3:25 pm
Connect all of the V+ to the positive rail, and all of the V- pins to the negative rail. You can't assume those bond pads are connected inside the IC package or silicon die with a low resistive path. You run the risk that some parts of the internal circuit are powered up, and others are not. Even if they were connected internally, now all the current drawn by the device is concentrated on one pin, and that pin might get hot enough to melt the solder joint.
NC stands for no connect, don't connect these pins to anything else.