Building a robot that will run on 12V. Using four DC motors and basing my design around an older robot that has been around my school for many years. It uses the LM 298 H-bridge for motor control.
I like the simplicity of the LM 298 but was wondering if there might be a better device I should be looking at or if it's still a good choice.
What are the attributes I should be looking at for best performance?
I presume you mean the L298 H bridge. It's generally a very poor choice compared to what is available nowadays. The basic problem with this (and the L293 and SN754410) is that as soon as you take any meaningful current from the output, the power transistors become inefficient and you might lose 3 volts per H-bridge when powering a 1A load. Look at page 3 on this - look down the bottom of the page at this: -
In red are the specs that I refer to. Note that the total volt drop can be as high as 3.2 volt for a 1A load. This means if you have a 12V supply and 12 motors, you'll not see much better than 9V across the motor.
Try looking at the DRV8800. It can drive up to 2.8A and each MOSFET has an on resistance of about 0.5 ohms - this means that a full H bridge loses maybe 1V. There are other devices that are worth looking at too. Check out TI's offerings and definitely go for MOSFET output drivers.
