I recently built up a pcb with a bunch of H-brides, but there's an issue with one of the ICs - when I power it on, both the outputs are shorted to ground! When the power is off, there is no short, but with power, there's only about 2 ohms between the outputs and ground. Does anybody know what could be going on here?
Also, when I send a signal to one of the inputs using an AVR, I read 3.6 volts on BOTH the inputs (I'm using a 5V VCC). On another chip that does work, I read a normal 5V on whichever input I turn on. I don't detect any shorts between the MCU pins.
Hi, going to need more info.
jpg, png or pdf of your circuit diagram and PCB pattern.
Sounds like the chip is in brake mode, both outputs shorted together, usually to gnd or Vcc as well. So I would check pattern around input pins.
Have you swapped or changed IC to see if problem is IC or PCB?
Here's the pic of the schematic: http://imgur.com/zun2dtD- the board layout is fine, I checked it thoroughly for shorts. I did swap out the IC, but the same thing happens. I think the problem might be in the microcontroller - perhaps I overheated it whilst soldering (I used paste and hot air) resulting in a couple of dead pins? That could explain the funny voltages on the inputs...
