Problems with DRV8313 on PWM12

I have used DRV8313 in a project before and it worked well, but on my PWM12 Hat I seem to have 2 busted chips so far. I selected both from the same batch, so I will add a 3rd from a different batch and see if it works.

PWM12 is a very simple Hat and DRV8313 is straight forward to use. I will not know the answer to this before I get a circuit working, but I suspect a bad batch again. One indication is that the two I have used so far behave differently. The first output ca 1.75V, while the other output 0.

It is a reminder that I should stop buying advanced chips from Asia on aliexpress. Luckily I have 4 different batches, and I don’t know if this is the cause yet.

Update 1: Adding the 3rd circuit I get the same output as from #2. #1 have an offset the others do not have. What puzle me is that I have absolutely no signal from any of the DRV8313 chips and this was 2 different batches. I can measure input voltage, I can measure that nRESET, nSLEEP and EM4 signals are correct. I can also see the pulse – that shoul be it – I should see an amplified pulse on output. You see the schematics for the circuit #4 above – it is seriously not much to this.

I also notice that I draw ca 70mA with 3 x DRV8313 connected regardless of what signals I give. It is almost as if I have done a systematic or common error on all 4 circuits. Luckily I have a different motor controller (MC3X3A) that uses the same chip and is working, so I need to use this as a reference. In absolute worst case I will re-solder a verified, working DRV8313 over to a PWM12 board.

Update 2:I have added the 4th circuit from yet another batch with the same problem. I see an unusual power usage – ca 25mA (ca 6mA on the one that works) and no response. All signals in are ok – Power, ground, Enable, Reset, Sleep and PWM. My next step is to solder up a motor controller and using a DRV8313 there for so to move it to a PWM12 Hat. In addition just let the problem rest a bit and look at it with fresh eyes one of the following days. I suspect that I have done something blunt stupid and simple, but I can’t find it – yet.

Update 3: I moved a DRV8313 that was not working on PWM12 over to the motor controller and it works perfectly! Meaning it is something with my schematics or PCB layout that is off on all 4 circuits. In one way that is a relief because it means my batches are good – at least some of them. Now I just need to figure out what is wrong on PWM12.

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