Hi,
It's possible in my application that each output of DRV 8860 will face the maximum continuous load allowed as per datasheet. So the maximum possible current floating back to GND is 330mA x 8 or 2.54A dc.
The PCB trace connecting pin 5 to the heat sinking copper pad is fairly narrow of about 0.016". My concern is that if pin 5 is the only one handling the full return then that total current will flow to the GND layer through that narrow trace. Given that the fusing current of the 2 oz 16-mil-wide trace is very close to the return current value, I'm wondering if I have a potentially risky situation. On other side, if return current is handled by the PowerPAD pin, the thermal pad size will eliminate any worries as the cross-section area would be sufficient to handle the total return current. So my questions are as follows.
Q1. Does PowerPAD pin at the bottom of the chip carry any portion of the total load return current back to the system ground or is it the GND pin (pin 5) that is wholly responsible for handling that current?
Q2. In case if pin 5 to provide a return path, is my concern valid or is heat sinking capability of the copper pad under the IC typically sufficient to prevent fusing?
Please advise and thank you for your support.
Regards, Michael
