Hi, I am working on a dcc decoder, all things seem to be working fine, except the motor driver. When i wanted to test it on a 100% duty cycle, in the moment i connected it to the motor, it blew up leaving a hole in its case. The board itself continued to function normally no damage done to other components, only the DRV8220. When i measured output voltage of the burnt driver it was 0v. Can someone please help me resovle this problem? The driver is only thing sopping me from completing this project.
Thanks in advance.

 

Welcome to AAC!
Why is there a ground symbol at input pin 2 of the voltage regulator?
The 12V supply doesn't have the bulk capacitance specified in the datasheet.
Are you using a heatsink?
What is the motor specification (Volts, Stall/starting current)? Note: start-up current is always a lot higher than normal running current.
That driver IC has a rather high specified On-resistance of 500mΩ, so will create considerable heat if motor current is high.

 

The voltage regulator in the schematic is not the one I actually use, it is there only because it has the same footprint. Therefore the wiring is for the one I use.
I don't actually use a bulk capacitor. What capacitance will be the best to use?
No, I am not using a heatsink. I am not sure about the specification of the motor, it is a standard brushed motor used in model railroading. It should be rated for something around 1-20v.

 

Therefore the wiring is for the one I use.

Which one is that? If you don't show the components you are actually using, at least tell us the alternative, or you are likely to get misleading answers.

it is a standard brushed motor used in model railroading

The 'standard' may not be. Can you post a link?
As for the bulk capacitance, that is likely to depend on motor surge currents.

 

There's only enough bulk capacitance on the 12V line to sustain a current of 75uA to keep the driver from going in and out of UVLO.
Perhaps going in and out of UVLO 100 times a second is making it blow up!
Is it a 12V AC supply? Is it 12V rms? If so, when rectified, it's awfully close to the maximum supply voltage of the DRV8220

 

The voltage regulator I use is DI78M05UAB. All the other components in the schematic should correspond to those i use. The only data I could find about the motor is rated for 9v and 0.12A. But as the board is supposed to be a decoder that can be installed on any locomotive it should handle a variety of motors.
The power supply I used in the test was 16V DC. In normal operation, it will be a 16V digital signal, that gets rectified and the signal is isolated and processed by the attiny

 

So you are using a chip with max supply voltage of 10.8V to drive a motor rated at 9V with a supply voltage of 16V. What could possibly go wrong?

 

If I am not mistaken the max supply voltage of drv8220 is 18V. And the motor has a range of around 1.2V-18V.