Im trying to repair a rc car. It has a single 12V dc motor (12V is too fast, im powering it with 6v) which draws 200-300 mA of current on a normal day. When i put the motor under heavy load (use my hands to stop the motor) it draws about 1.2A. So im thinking of putting two L293D's in parallel. Do i just solder every pin with each other? Will that distribute the heat equally between two IC's?
Don’t, they won’t share the current.
I got too many L293D's in my hand is there any way i can use them in this application?
I don’t see how.
If you parallel transistors or darlingtons the ones that happen to take more current get hotter, which increases the current in them leading to positive feedback till most of the current flows in one only. The way this is solved is adding emitter resistors to enforce better sharing (at the expense of power wasted in the resistors).
Its not a very desirable solution for darlington drivers which already waste a shed-load of power.
MOSFET H-bridges are the way to go for higher current motor driving. Pololu have a reasonably comprehensive range for instance, up to 30A or so IIRC.