Our contract manufacturer incorrectly populated the RC external circuitry on the RCA and RCB pins. Instead of R = 13.7k and C = 680pF, they used two R = 13.7k resistors. So, there is no capacitor there, instead just another resistor.
Looking at the waveform with the two resistors using a current probe, I can see that there is no decay/current ripple to the motor, as expected with no C. However, when I connect our motor to this circuit, this circuit provides much higher torque than the correct circuit.
A few questions:
- What is the reasoning behind this?
- Is the bridge being PWM'd at all? It doesn't appear so.
- Are there ramifications to using just an R instead of RC on those pins, i.e. can the motor or IC be damaged?