MCF8316A: I2C INTERFACE AND CONTROL PIN CONFIGARTION

Michele Mocellin

Part Number: MCF8316A

Hello,

if I use I2C bus to configure and control the driver, what is the best configuations for the other control pins BRAKE, DRVOFF, DIR, EXT_CLK, EXT_WD and SPEED/WAKE, LOW or FLOATING ?

And if I do not use monitoring pin FG, nFAULT and SOX, what is thir best configuration ?

Thank you

over 3 years ago

0 Vishnu Balaraj over 3 years ago

TI__Mastermind 24415 points

Hi Michele,

Here's my feedback.

BRAKE - Connect to PGND via 10-kΩ resistor, if not used

DRVOFF - Pull to GND

DIR - Connect to AVDD via 10-kΩ resistor, if not used

EXT_CLK, EXT_WD - Leave them floating

SPEED/WAKE - Leave floating or pull HIGH to AVDD

FG, nFAULT and SOX - Leave them floating

Regards,

Vishnu

0 Michele Mocellin over 3 years ago in reply to Vishnu Balaraj

Prodigy 90 points

Thank you,

another question regarding GND, what happen if I don't divde PGND and AGND but I use a single GND plate for both ?

0 Andrew Liu over 3 years ago in reply to Michele Mocellin

TI__Mastermind 18981 points

Hi Sujeesh,

Some of our team members are currently out for travel with customer visits,

But for now, I recommend taking a look at these two resources for GND scheme on PCB design

There will be some information to answer your question

https://training.ti.com/how-conduct-bldc-motor-driver-schematic-review-and-basic-debug-tip (videos on right-hand side)

https://www.ti.com/lit/an/slva959b/slva959b.pdf

https://www.ti.com/lit/an/slvaf66/slvaf66.pdf

For GND scheme specifically, I believe the main difference will be:

single combined GND will have better thermals, but noise coupling is possible between motor switching (Power GND) and analog/digital networks (Analog/Digital GND) which affect CSAs, Regulators, etc...
split GND will have better signal performance but worse thermals

Best Regards,
Andrew

0 Vishnu Balaraj over 3 years ago in reply to Michele Mocellin

TI__Mastermind 24415 points

Michele,

We recommend having two separate ground planes for AGND and PGND to reduce noise coupling and EMI interference from large transient currents into small-current signal paths.

Regards,

Vishnu

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MCF8316A: I2C INTERFACE AND CONTROL PIN CONFIGARTION