View Full Version : Allegro Chip vs. MB15027GN

12-02-2007, 10:18 PM
As some of you may have seen from my other posts I am very new to this. Iam starting with a Grinch board and have just ordered it along with 16ssr boards to get me my 64 channels. Next I was getting the parts list together so I can order everything.

I was reading the the instructions in the announcement post, but it says to use 4 MBI chips. As I read through the other posts everyone is discussing the use of allegro chips instead.

What is the difference, and is it O.K. for me to use these instead of the MB15027GN (available at King Electronics). If so I too am going to try to get the 6 free samples, but if not no big deal.


12-02-2007, 10:21 PM
The MBI's are very voltage sensative i had to drop down to 4.46 volts to get them to work with the allegro chip i got my free sample in a few days and now i run my power supply 5 volts off my pc I perfer the allegro chip over the mbi just because of the sensitive volts

12-02-2007, 10:32 PM
Thanks I am going to try to allegro chip. It is even better if I am actually able to get the free samples as a few of you have said you were able to.

BTW while you mentioned power. This is probably a simple question, but I know where the power goes into the board, but how do you physically get it from the CPU power supply. Basically what do you wire from and to? And please put it in simple terms I am trying to learn here and will not be insulted by even the simplest instruction.


Wayne J
12-02-2007, 10:47 PM
You will have to open your PC. Inside there will be 'spare' power plugs. These plugs usually carry +5 and +12 with two grounds. You will want to tap into a ground and the +5v and run that to your board. The square pad on the Grinch is the +5.

12-03-2007, 12:05 AM
Most computer case fans have a pass-through pigtail they use to tap into the 12v power of a hard drive connector. If you can find one from an old computer you can salvage the end to plug into your computer. No need to cut your computer's wires. You can also buy one from your local computer shop, I just think recycle first.




12-08-2007, 10:17 PM
I just got my free sample allegro chips in the mail today and it happened to be the same day I got the boards in the mail from wjohn. All I have to wait for now is the order from mouser and I am ready to learn how to solder :). Oh well I am really getting excited now that I actually have something physical in my hands!!!!!

12-09-2007, 08:51 PM
which allegro chips did you choose?

12-10-2007, 07:09 PM
Part # A6279EA-T-ND

It is the same alternate part that John has listed in his construction notes document that is in the sticky of this section of the forums.