Newbie- A3977 Questions?

[khite]

So on pminmo.com it stats the the stepper driver A3977 can only handle upto 2.5A. When I read the manual it talks about using a fan if current is higher than 2.5 and pmdx.com,http://www.pmdx.com/PMDX-150, has a board that can handle up to 3A. My question is,

1. can I use the design from pminmo.com, http://pminmo.com/forsale/1X72805c.pdf, and use it at 3A with the proper cooling?

2. What is the difference between the pminmo.com and pmdx.com design?

3. If I use the pminmo.com design what size power supply. I am designing one from the DCS1 at pminmo but need to know what voltage to determine the resistor values

Thanks

[spainguy]

The A3977 data sheet states :
ABSOLUTE MAXIMUM RATINGS
at TA = +25°C
Load Supply Voltage, VBB ............. 35 V
Output Current, IOUT .................. ±2.5 A*

So do not attempt it, fan cools the IC, and use a PLCC heatsink like http://uk.farnell.com/fischer-elektr...c-w/dp/1222501

[Jesse B]

The A3977 uses a ground plane on the bottom of a chip for cooling, so heatsinks only help so much. The best way to cool these chips is with a large ground plane, which leads to a larger PCB. I wouldn't not attempt running more than 2.5A, which is higher that would be recommended regularly. 2A would probably be the highest you'd want to pull through these for any extended period of time.

If you need more amperage, there are plenty more affordable options out there.