Lm3886 Pcb

[soundNERD]

OK, I revised the PCB. Heres what I got.

There is a jumper from the gnd to pin 7 and from pin 7 to the resistor to its right.

Will this work fine?

Also, should i connect pins 2, 6 and 11 to gnd also? they don't connect to anything?

Thanks, Mike

[soundNERD]

anybody?

I know i havent added the decoupling caps, but i am going 2

[soundNERD]

Can somebody just tell me if the NC pins should be connected to GND or not?

[bigparsnip]

the nc pins shouldn't be conected to ground or anything else if you can avoid it (just to be on the safe side), however, if you want to fix the chip onto the PCB more solidly, you can just have unconected pads for each of these pins, and solder the legs as normal (as they still won't be conected to anything, kind of like it looks like you have done.

Also, where will you be running the wire from the gnd to the resitor through? will it still be going between the chips legs, as if it is a bare wire it may touch one of them and cause a short or someting.

edit:

Just a thought, what design software are you using?

Also, could you possibly post a scheematic, if you have it, so that it is a bit easier for us to see where things should be going in your design.

[peranders]

You should always read datasheet if you have "NC" pins. Sometimes you can use them as guard (some opamps), sometimes the are not used normally but it can also mean "do not connect" meaning DO NOT connect. They can be connected to something internally for production test maybe.

[soundNERD]

The schematic i used is from the first page of the datasheet. I am at a library computer now, so I don't have it.

I use the software called PCB Editor.

I will use insulated wires for jumpers.

I didn't think the NC pins had to be connected, but just wanted to make sure.

[bigparsnip]

Hi, I've just tried to have a real look at this and see where the components go and where the external connectors are, and I have realy confused my self, do you have a component overlay to go with this as (assuming it uses all of the smae components as on the national data sheet) it would prove very useful here I think.

[bigparsnip]

Right, I have had a quick bash from scratch using the national reference design from the scheematic, and come up with the board below, which should also allow for reasonalbe sized local power supply decoupling caps to be fitted, as well as having mute circuitry (simply wire in the switch between pads 3 and 4) input conector (signal and ground, on pads 1 and 2) output pads (signal and ground, pads 5 and 6) and the power supply conectors (pads, 7 8 and 9).

If you want a copy of the eagle board files, or the schematic just let me now and I can post them up here for you.

Andrew.

[bigparsnip]

Here is the board without the component overlay, to give you a clearer look at what is going on below.

edit: the red wire is a jumper link to simplfy the board layout a bit, but you could get away with un-insulated wire, as it will be no where near coming into contact with any other bare metal.

[bbksv]

Hey bigP...would you mind sending me that eagle file to bbksv@comcast.net........pretty please...