SN754110 claims it has internal clamping diodes - this means I don't need diodes in my circuit, right?

The datasheet for the motor driver SN754410 says that it has internal clamping diodes. My assumption is that if I use this IC, it has already taken care of the diode business for me and I can use it without worrying about that. Is this correct, or is this one of those things where you can't trust what the manufacturer says and have to put your own safety diodes in anyways?

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Comment by Shayegan (TA) on January 27, 2011 at 3:14am: Long answer:

Your worries about the internal clamping diodes on this component are definitely well-placed. On page 2 of the datasheet (http://focus.ti.com/lit/ds/symlink/sn754410.pdf), it is clear that internal diodes do exist on the outputs of this IC. For your own reference, such diodes placed across an inductive load are called flyback diodes, meant to protect the circuitry from voltage spikes. So at first glance it appears that you would not need external flyback diodes with this IC, unlike some other H-bridge ICs.

However, based on the application circuit on page 6 of the datasheet, it appears that external diodes are indeed needed. Generally, good idea for most ICs is to Google them and look for application websites. In this case, some of the sites I found indicated that the internal diodes on this component are only used for electrostatic discharge, even though they may work as flyback diodes. Here's one example site: http://www.ladyada.net/make/mshield/use.html. The site states:

"After careful reading of the datasheet and discussion with TI tech support and power engineers it appears that the output diodes were designed for ESD protection only and that using them as [flyback]-protection is a hack and not guaranteed for performance."

Short answer:

While using this IC without external flyback diodes will probably work, it is likely a good idea put in your own diodes as an extra safety measure.