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L298 Flyback Diodes

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Wp100

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Hi,

Am building a Dcc model train controller using a L298 as the output stage which feeds its output onto the rails. The pulses are received by decoders in the locos, the input to which is typically a bridge recitifer.

Because there is no direct motor connection to the L298 is it still necessary to fit the Flyback diodes ?

Have seen several working designs, some fitted with these diodes, some without ...?

Thanks
 
Your train motor is inductive. I would use the diodes.
 
why won't that piece of crap die???? the L29x family of motor chips are GARBAGE!!!

ST L297 $10 +L289 $5 for 4A TOTAL current + flyback diodes and a heatsink, half stepping

Allegro A3982 $6 1.5A per coil, synchronous flyback (no diodes required) and microstepping included!
 
Diodes are a good idea, but since there is a lot of electronics between the DCC powered track and any motor, I see no harm in leaving them out. It would be good to have them if there are any other loads powered by the track.
why won't that piece of crap die???? the L29x family of motor chips are GARBAGE!!!

ST L297 $10 +L289 $5 for 4A TOTAL current + flyback diodes and a heatsink, half stepping

Allegro A3982 $6 1.5A per coil, synchronous flyback (no diodes required) and microstepping included!
The DCC model train system is not a stepper motor. Microstepping would certainly screw it up.
 
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Diodes are a good idea, but since there is a lot of electronics between the DCC powered track and any motor, I see no harm in leaving them out. It would be good to have them if there are any other loads powered by the track.The DCC model train system is not a stepper motor. Microstepping would certainly screw it up.

so use a DC PWM version of the chip, the fact remains that the L298 chip is an archaic piece of junk. ... sorry I just equated the two since they are normally used together
 
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