> Where does it say that in the datasheet? Hi, Nathan. Take a look at Figure 3. Also, have a look at the SGS L293, which the SN754410 is compared with www.st.com/stonline/books/pdf/docs/1328.pdf and the L298 www.st.com/stonline/books/pdf/docs/1773.pdf > I bought a bunch of 1A schottky diodes on ebay, will those work > as well as the MUR1560 you mentioned? Better would be the UF400x series. Same packages as 1N, but fast The MUR1560 is a fairly hefty fast diode, 600V, 15A. I mentioned it as one type of drive I use is PWM with a large FET and a 1/2HP 12VDC motor. It generates a lot of back-EMF and hash noise, which the diode takes care of, leaving the FET largely unaffected. Schottky diodes, ISTR, have no recovery time. However, the application notes of the ICs above do not use Schottky, but ultrafast. FETs can be more sensitive than bipolars in some instances and need over-voltage protection so I tend to use both low Vf and fast diodes. No failures yet, touch wood. It's cheap insurance anyway > Do you put the filter cap (.1uF?) on the motor itself or on the pcb > where the motor wires connect? The best place to get rid of noise is at the source. Doing it there will help prevent noise being radiated from wiring. I would suggest a cap, say 100nF ceramic, across the motor terminals, and also one from each terminal to the motor case. Another option is to add a pair of back-to- back zener diodes across the terminals. The value will depend on what voltage the motor is driven with and what noise voltage you want to suppress. For a 12V motor, perhaps 15V terminal - cathode - anode - anode - cathode - terminal > Also, do you think it would be a bad idea to power the motors and > microcontroller from the same power supply (batteries)? With adequate filtering it should be OK. The only issue might be when the motor turns on or if it stalls. There could be big dip in the supply. Generally the micro will cope if it's above the brown-out voltage, although watch out for noise on MCLR if you have it enabled or any noise on inputs that could affect operation. A dip in power at start-up could probably be avoided by ramping up the power to the motor with PWM (ie soft start) If possible, you could isolate the SN754410 supply from the micro with a couple of diodes (Schottky would be lower Vf than a silicon at higher amperage) and give the SN754410 and motor their own reservoir cap micro - cathode - anode +V+ anode - cathode - IC/motor Joe --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .