I wish to use the 8814 in a dual motor robot platform. However, I will be running this at a voltage of 6 VDC for the motors and 5 VDC for the logic. The datasheet states a minimum of 8 VDC for this motor driver. Can I use the lower voltage to drive the motors? I also have two motors drawing up to 2 amps per motor. What size heatsink would you recommend? What would be the minimum component version for use with PWM?
Hi Ed,
The DRV8814 will definitely not work at 6V. Luckily, we have a part which will do precisely what you need and at the voltages/currents you require. The DRV8834 is a dual H Bridge driver with superb flexibility. On the same package you get the ability to operate the H Bridges either in stand alone mode to drive two DC motors or a stepper with external indexer microstepping commutation, or a fully integrated bipolar stepper driver with up to 32 degrees of microstepping. This device will offer you up to 2.5A sine wave peak with no problem. It should also be able to handle the 2A continuous per motor as long as thermal management is taken into consideration.
For heat sinking, the board must be designed with enough copper which will work as the path to extract heat from the package and into the outer world. I recommend you look into the SLMA002 Application Note which has good pointers as to how to design your PCB. A heat sink on top of the device will not do much as the plastic package's thermal impedance is too high. Heat must be extracted through the bottom, and the Power Pad.
Hope the info helps. Best regards,
Jose Quinones