What is the difference between L6470 and L6472?

tobozocska · ‎2018-01-14

Posted on January 14, 2018 at 20:54

I see that there is a difference in the number of microsteps and if they drive/control voltage or current, but is there any other difference? Could please somebody give me a quick comparison between them?

I originally bought L6474 as I thought that is the most advanced (increasing numbering), but I figured out from one of the 7 datasheets and user guides in front of me, in one footnote, under a table, in the middle of the page(!), that it is not entirely controllable by SPI. So is the l6470 the most advanced (reverse logic)? Or is it the L6472 (no logic at all)?

And how can I get 2-4 engineering samples as the site which should be destined for that doesn�t seem to work for months and I already wrote a feedback about that as the FAQ suggested for the preferred way to report bugs� and now I have to buy them at a 3-4 times higher price from sinuss.nl

#l6470 #bad-support-problems-errors #l6472

Phlip Cornelissen · ‎2018-01-15

Posted on January 16, 2018 at 08:16

The difference between the L6470 and L6472 is just that, one is a current control mode version and the other a voltage control version. Of cause the voltage control mode gives one the option of higher micro steps than the current control mode. I use the L6480 and L6482 which is the same as the L6470 and L6472 except that the mosfets are now external, so you can choose your own mosfets to use.

I did scan through the datasheet of the L6474 to have a look at the serial interface. I did not see any other option than the standard SPI interface. Have a look at the following application note: AN4241. The following application notes may be of some help to you: AN4144, AN4158.

Hope this helps.

tobozocska · ‎2018-01-16

Posted on January 16, 2018 at 14:28

Yes, it did help to understand the difference between L6470 and L6472 , thank you! Can you suggest some guide on how to choose the right mosfets, if I decide to choose a driver which doesn't have built in mosfets? I guess the external mosfets help on cooling if you add heatsinks to them?

About the L6474, in application note AN4290, on page 5, under the table, there is a little surprise for you too

Phlip Cornelissen · ‎2018-01-16

Posted on January 16, 2018 at 14:59

If you want to use drivers (like the L6480 or L6482) that use external mosfets there is a crucial rule that must be taken into account and that is the total gate charge (Qg) of the mosfet. This determine the amount of current spike the driver needs to supply into the gate of the mosfet to be able to turn it on properly. According to the L6480 or L6482 datasheets both can drive a mosfet with Qg of about 50nC. My suggestion though is not to go higher than 30nC if possible, choose a mosfet with as low a Qg as possible! Now the L6480 and L6482 drivers have the option where you can configure the amount of current supply and the duration (microseconds) of current supply to drive the mosfet. If this is not properly setup you will continuously get over current detection errors because the transistor does not switch on fast enough. Use as long as possible drive time and low current as a starting point and work your way up to higher drive currents until your system works properly.

If you are going to develop your own boards make sure the tracks between the driver and mosfet gate is as short as possible and also the thicker the better, this reduces the delay in charging of the mosfet gate.

About the L6474 SPI communication I misunderstood you regarding the control capability of the device as it has a full SPI port but very limited in functionality, meaning the functions available to control the device is not that much. That's why the datasheet only list the commands available on pages44-46, the rest is not built in on the L6474.